Method of making a pultruded part with a reinforcing mat

ABSTRACT

A method of making a pultruded part having a uniform cross-section using a novel reinforcing mat. The method comprises orienting a plurality of longitudinal rovings along a longitudinal axis of a pultrusion die; providing a reinforcing structure comprising a permeable transport web of staple fibers attached to a plurality of first reinforcing fibers oriented so that the portion of the first reinforcing fibers oriented in a direction transverse to the longitudinal axis comprises at least 40% of a volume of materials comprising the reinforcing structure; shaping the reinforcing structure to generally conform with a profile of the pultrusion die; combining a resin matrix with the longitudinal rovings and the reinforcing structure in the pultrusion die so that the longitudinal rovings and the reinforcing structure are substantially surrounded by the resin matrix; at least partially curing the resin matrix in the pultrusion die; and pulling the pultruded part from the pultrusion die.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. applicationSer. No. 09/597,453, entitled Pultruded Part and Method of Preparing aReinforcing Mat for the Part, filed Jun. 20, 2000, which claims priorityof U.S. Provisional application Ser. No. 60/155,258 filed Jun. 21, 1999.

FIELD OF THE INVENTION

The present invention relates to a method of making a pultruded partwith a novel reinforcing mat.

BACKGROUND OF THE INVENTION

Pultrusion is a known technique in which longitudinally continuousfibrous elements, which can include reinforcing fiber and/or a mat, arecombined into a resin-based structure. The process generally involvespulling reinforcing fibers and/or reinforcing mats through a bath ofthermoset resin and then into a heated forming die. The heat of the diecures the resin as the part is pulled through the die on a continuousbasis.

The mat and reinforcing fiber are typically flexible and conformabletextile products since they need to conform to the profile of the die.The mat and reinforcing fiber are typically glass products, while theresin matrix is usually, but not necessarily, a thermosetting polyester.Mat material is generally in the form of a non-woven, felt-like webhaving glass fibers randomly placed in a planar swirl pattern.

During the pultrusion process, reinforcing fibers typically referred toas rovings comprise groupings of hundreds or thousands ofmicrons-diameter filaments, that mechanically behave like flexible rope.The filaments are flexible because the diameter of each filament is sosmall. The flexibility of the individual filaments imparts sufficientflexibility to the reinforcing fibers to fulfill the processingrequirements of pultrusion. In a pultrusion profile, the mat and rovingsconstitute the reinforcement, while the resin constitutes the binder ofthe solid composite. After pultrusion, the rovings are held together bythe cured or semi-cured resin matrix, providing the pultruded part withrigidity.

The longitudinal strength of pultruded parts is very high since themajority of the fibers are the longitudinally extending reinforcingfibers that are pulled through the die. However, the transverse strengthof pultruded parts is generally minimal because conventional mat fibersextend in random directions and only a small proportion of the totalfiber component extends in the transverse direction.

Conventional mats also have a number of problems that interfere with theefficiencies of the pultrusion process. First, the mat is relativelyexpensive. Second, the mat is difficult to form into the required shapefor complex parts. The compressed thickness of the mat also represents alower limit on the thickness of sidewalls, increasing the amount ofresin needed for a given part. Lightweight continuous filament or“swirl” mats are easier to shape, but provide minimal strength, and aremore prone to ripping at the die entrance due to low wet tensilestrength. The choice of mat is, in part, a compromise between thenecessity for bending to shape, the required strength of the pultrudedpart, and the pulling strength of the reinforcing mat.

U.S. Pat. No. 5,005,242 (Vane) reports a reinforcing mat having aplurality of superimposed layers. Each layer consists of a plurality ofuni-directional non-woven yarns or threads laid side-by-side. The yarnsin at least some of the different layers extend in different directions.The layers of reinforcing material are stitched together by knitting soas to hold the yarns in fixed position relative to one another. The matdisclosed in Vane exhibits strength primarily in the direction of theuni-directional yarns.

U.S. Pat. No. 5,908,689 (Dana et al.) reports a mat adapted to reinforcea thermosetting matrix material. The mat includes a primary, supportinglayer having a plurality of randomly oriented essentially continuousglass fiber strands. The primary layer is about 1 to about 20 weightpercent of the mat on a total solids basis. A secondary layer ispositioned upon and supported by a surface of the primary layer. Thesecondary layer includes a plurality of glass fiber strands having amean average length of about 20 to about 125 millimeters. The strands ofthe primary layer are entangled with the strands of the secondary layerby needling the primary layer and the secondary layer together.

U.S. Pat. No. 5,910,458 (Beer et al.) reports a mat adapted to reinforcea thermosetting matrix material. The mat includes a primary layer ofgenerally parallel, essentially continuous glass fiber strands orientedgenerally parallel to a longitudinal axis of the mat. The primary layeris about 45 to about 90 weight percent of the mat on a total solidsbasis. A secondary layer includes a plurality of randomly oriented,generally continuous glass fiber strands. The strands of the primarylayer are entangled with the strands of the secondary layer by needling.

U.S. Pat. No. 4,058,581 (Park) reports adding discontinuous fibers tothe resin bath. Similarly, U.S. Pat. No. 5,324,377 (Davies) reportsmixing cut fibers in the resin bath to form a homogeneous mass of resinand fibers. The continuous fibers, the cut fibers and the resin are thenpassed through a die and become integrated into a pultruded part.

In order for the reinforcing mat to pass through the die with thelongitudinal fibers, it is necessary for the mat to have a sufficientlongitudinal strength so that it does not tear as it is pulled throughthe die. Furthermore, the mat must have a sufficient shear strength sothat it does not twist or skew allowing one side edge of the mat to movein advance of the other side edge. If such twisting or skewing occurs,the mat will become distorted in the part and the mat eventually willbreak down and the part will be unusable.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a method of making a pultruded parthaving a uniform cross-section. The method comprises orienting aplurality of longitudinal rovings along a longitudinal axis of apultrusion die; providing a reinforcing structure comprising a permeabletransport web of staple fibers attached to a plurality of firstreinforcing fibers oriented so that the portion of the first reinforcingfibers oriented in a direction transverse to the longitudinal axiscomprises at least 40% of a volume of materials comprising thereinforcing structure; shaping the reinforcing structure to generallyconform with a profile of the pultrusion die; combining a resin matrixwith the longitudinal rovings and the reinforcing structure in thepultrusion die so that the longitudinal rovings and the reinforcingstructure are substantially surrounded by the resin matrix; at leastpartially curing the resin matrix in the pultrusion die; and pulling thepultruded part from the pultrusion die.

In another embodiment, the portion of the first reinforcing fibersextending in the transverse direction comprises at least 50% of a volumeof materials comprising the reinforcing structure. In anotherembodiment, the first reinforcing fibers comprise one or moreoverlapping layers of first reinforcing fibers.

In one embodiment, the staple fibers comprise a length of about ½ inchto about 4 inches. In another embodiment, the staple fibers comprise alength of about 0.01 inch to about 12 inches. In one embodiment, thestaple fibers comprise a weight of about 60 grams per square meter toabout 300 grams per square meter before attachment to the firstreinforcing fibers. In another embodiment, the staple fibers comprise aweight of about 10 grams per square meter to about 1200 grams per squaremeter before attachment to the first reinforcing fibers.

The permeable transport web can optionally comprise heat-fusible fibers.In another embodiment, the permeable transport web comprises at leasttwo different polymeric fibers, each comprising a different glasstransition temperature. In one embodiment, the two polymeric fiberscomprise a glass transition temperature of about 350° F. and about 270°F., respectively. In another embodiment, the permeable transport webcomprise a plurality of first polymeric fibers comprising a first glasstransition temperature a plurality of bi-component fiber. The firstcomponent comprises the first glass transition temperature and a secondcomponent comprises a second glass transition temperature less than thefirst glass transition temperature. The bi-component fibers optionallycomprise a core-sheath configuration.

The reinforcing structure preferably comprises in-plane mechanical anddirectional stability. The permeable transport web preferably comprisesa plurality of fibers at least a portion of which are randomly entangledwith the first reinforcing fibers. In another embodiment, the permeabletransport web comprises a plurality of fibers at least a portion ofwhich are thermally bonded to the first reinforcing fibers.

In one embodiment, the first reinforcing fibers are spaced apart andattached together by a continuous stitching fiber. The stitching fibercomprises glass fibers, natural fibers, carbon fibers, metal fibers,ceramic fibers, synthetic or polymeric fibers, composite fibersincluding one or more components of glass, natural materials, metal,ceramic, carbon, and/or synthetics components, or a combination thereof.In another embodiment, a binder attaches the permeable transport web tothe first reinforcing fibers. In one embodiment, the binder comprisesone or more of a specialized latex binder diluted in a water carrier, apolyvinyl acetate emulsion, or a crosslinking polyvinyl acetateemulsion.

The reinforcing structure includes a plurality of perforations throughthe permeable transport web and extending between the first reinforcingfibers. In one embodiment, the reinforcing structure comprises apermeability of at least 180 ft³/minute/ft² as measured according to theprocedure of ASTM D737-96 with a pressure differential of about 0.5 inchcolumn of water. In another embodiment, the permeability comprises about300 ft³/minute/ft² as measured according to the procedure of ASTMD737-96 with a pressure differential of about 0.5 inch column of water.In yet another embodiment, the reinforcing structure comprises apermeability of more than 350 ft³/minute/ft² as measured according tothe procedure of ASTM D737-96 with a pressure differential of about 0.5inch column of water.

In one embodiment, the reinforcing structure comprises a circularbending stiffness of at least about 4 Newtons as measured according tothe procedure of ASTM D4032-94. In another embodiment, the reinforcingstructure comprises a circular bending stiffness in a range of about 4Newtons to about 15 Newtons as measured according to the procedure ofASTM D4032-94.

In one embodiment, the reinforcing structure comprises a thickness ofabout 0.004 inches to about 0.020 inches, and typically about 0.010inches to about 0.012 inches. The reinforcement structure preferablycomprises a tensile strength in the transverse direction of about 200lbs/inch as measured using the procedure of ASTM D76-99. Thereinforcement structure comprises a tensile strength in the pulldirection of at least 6 lbs/inch as measured using the procedure of ASTMD76-99.

The first reinforcing fibers comprise glass fibers, natural fibers,carbon fibers, metal fibers, ceramic fibers, synthetic or polymericfibers, composite fibers (including one or more components of glass,natural materials, metal, ceramic, carbon, and/or syntheticscomponents), or a combination thereof. In another embodiment, the firstreinforcing fibers comprise at least one polymeric component. The firstreinforcing fibers optionally comprise a surface treatment including anorganosilane agent. The organosilane agent comprises one or morefamilies of a cationic amino-functional silane,Tris(2-methoxyethoxyvinylsilane), or3-methacryloxypropyltrimethoxysilane.

In one embodiment, the transverse direction comprises a direction about90°+/−10° relative to the pull direction. In another embodiment, thetransverse direction comprises a direction about 90°+/−5° relative tothe pull direction. In some embodiments, substantially all of the firstreinforcing fibers extend continuously across a width of the reinforcingstructure. The reinforcing structure can optionally include a pluralityof permeable transport webs.

In one embodiment, a plurality of second reinforcing fibers extend atone or more acute angles relative to the pull direction. In thisembodiment, the second reinforcing fibers comprise a transportcomponent. In another embodiment, a plurality of second reinforcingfibers extend at a first acute angle relative to the pull direction anda plurality of third reinforcing fibers extend at a second acute anglethat is the negative of the first acute angle. A plurality of fourthreinforcing fibers extending in the pull direction can optionally beadded. In one embodiment, the first reinforcing fibers are locatedbetween the second and third reinforcing fibers.

In another embodiment, the reinforcing structure comprises a pluralityof second reinforcing fibers extending at a first acute angle relativeto the pull direction, a plurality of third reinforcing fibers extendingat a second acute angle that is the negative of the first acute angle,and a plurality of fourth reinforcing fibers extending generally in thepull direction. In one embodiment, the permeable transport web comprisesa plurality of fibers at least a portion of which are randomly entangledwith one or more of the first, second, third or fourth reinforcingfibers. In another embodiment, the permeable transport web comprises aplurality of fibers at least a portion of which are thermally bondedwith one or more of the first, second, third or fourth reinforcingfibers. In yet another embodiment, the first reinforcing fibers arestitched with one or more of the permeable transport web, the secondreinforcing fibers, the third reinforcing fibers, and the fourthreinforcing fibers.

In one embodiment, a binder is used to attach the permeable transportweb to one or more of the first, second, third or fourth reinforcingfibers. One or more of the first, second, third or fourth reinforcingfibers optionally comprise a polymeric component. The first reinforcingfibers can be located between the second and third reinforcing fibersand the fourth reinforcing fibers. The first, second, third or fourthreinforcing fibers typically comprise discrete layers.

The pultruded part typically comprises a wall thickness of about 0.045inches to about 0.025 inches. In another embodiment, the pultruded partcomprises a wall thickness of about 0.039 inches or less. In oneembodiment, the longitudinal rovings and the reinforcing structurecomprise alternating layers. In yet another embodiment, the reinforcingstructure is located adjacent to an outer surface of the pultruded part.The longitudinal rovings are optionally located adjacent to an outersurface of the pultruded part. In another embodiment, a plurality oflongitudinal rovings are adjacent to both surfaces of the reinforcingstructure. In another embodiment, alternating layers of reinforcingstructure and longitudinal rovings are arranged prior to combining withthe resin matrix.

In yet another embodiment, the method comprises arranging a plurality offirst reinforcing fibers in a transverse direction relative to the pulldirection and thermally bonding a permeably reinforcing sheet to thefirst reinforcing fibers. The reinforcing structure comprises apermeability of at least 180 ft³/minute/ft² as measured according to theprocedure of ASTM D737-96 with a pressure differential of about 0.5 inchcolumn of water.

In yet another embodiment, the method comprises arranging a plurality offirst reinforcing fibers oriented in a transverse direction andattaching a permeable transport web of staple fibers to the firstreinforcing fibers such that a ratio of a modulus of elasticity of thereinforcing structure in the transverse direction relative to a modulusof elasticity in the pull direction comprises at least 1.2. In anotherembodiment, the ratio of the modulus of elasticity of the reinforcingstructure in the transverse direction relative to the modulus ofelasticity in the pull direction comprises at least 1.5, preferably atleast 3 and more preferably at least 5.

In yet another embodiment, the method comprises arranging a plurality ofnon-overlapping first reinforcing fibers in a transverse direction andattaching a permeable transport web of staple fibers to the firstreinforcing fibers such that the portion of the first reinforcing fibersextending in a transverse direction comprises at least 30% of a volumeof materials comprising the reinforcing structure.

In yet anther embodiment, the method comprises arranging a plurality offirst reinforcing fibers at 45° (+/−15°) relative to the pull direction;arranging a plurality of second reinforcing fibers at −45° (+/−15°)relative to the pull direction; and attaching a permeable transport webof staple fibers attached to the first and second reinforcing fiberssuch that the first and second reinforcing fibers comprises at least 30%of a volume of materials comprising the reinforcing structure.

In yet another embodiment, the method comprises arranging a plurality offirst reinforcing fibers at 60° (+/−15°) relative to the pull direction;arranging a plurality of second reinforcing fibers at −60° (+/−15°)relative to the pull direction; and attaching a permeable transport webof staple fibers attached to the first and second reinforcing fiberssuch that the first and second reinforcing fibers comprises at least 30%of a volume of materials comprising the reinforcing structure.

In yet another embodiment, the method comprises arranging a plurality offirst reinforcing fibers in a transverse direction and attaching apermeable transport web of staple fibers to the first reinforcing fiberssuch that the portion of the first reinforcing fibers oriented in thedirection transverse comprises at least 40% of a volume of materialscomprising the reinforcing structure.

In yet another embodiment, the method comprises arranging a plurality offirst reinforcing fibers in a transverse direction continuously across awidth of the reinforcing structure and attaching a permeable transportweb of staple fibers to the first reinforcing fibers.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The invention will now be described in conjunction with the accompanyingdrawings in which:

FIG. 1 is a schematic, cross-sectional view of a pultruded part inaccordance with the present invention.

FIG. 1A is an enlarged a portion of the pultruded part shown in FIG. 1.

FIG. 2 is a further enlarged schematic detail of the pultruded partshown in FIGS. 1 and 1A.

FIG. 2A is a schematic illustration of an alternate pultruded part inaccordance with the present invention.

FIG. 3 is a schematic illustration of a pultrusion process and equipmentfor carrying out a method of the present invention.

FIG. 4 is a schematic illustration of a bottom view of a reinforcing matin accordance with the present invention.

FIG. 5 is a cross-sectional view of the reinforcing mat of FIG. 4.

FIG. 6 is a schematic illustration of a top view of an alternatereinforcing mat in accordance with the present invention.

FIG. 7 is a cross-sectional view of the reinforcing mat of FIG. 6.

FIG. 8 is another cross-sectional view of the reinforcing mat of FIG. 6.

FIG. 9 is a schematic illustration of a method of making a reinforcingmat in accordance with the present invention.

FIG. 10 is a schematic illustration of an entangling device inaccordance with the present invention.

FIG. 11 is a schematic illustration of a top view of a web suitable formaking a reinforcing mat in accordance with the present invention.

FIG. 12 is a transverse cross-sectional view of the web of FIG. 11.

FIG. 13 is a longitudinal cross-sectional view of the web of FIG. 11.

FIG. 14 is another cross-sectional view of the reinforcing mat made fromthe web of FIG. 11.

FIG. 15 is a schematic illustration of a top view of an alternatereinforcing mat in accordance with the present invention.

FIG. 16 is a cross-sectional view of the reinforcing mat of FIG. 15.

FIG. 17 is an enlarged, fragmentary, schematic representation of aneedle apparatus for forming holes through the thickness of areinforcing mat.

FIG. 18 is an enlarged, fragmentary view of a representative needleuseful for entangling staple fibers or cut fibers in a reinforcing matof the present invention.

FIG. 19 is a schematic illustration of a top view of an alternatereinforcing mat in accordance with the present invention.

FIG. 20 is a cross-sectional view of the reinforcing mat of FIG. 19.

FIG. 21 is a schematic illustration of a top view of an alternatereinforcing mat in accordance with the present invention.

FIG. 22 is a cross-sectional view of the reinforcing mat of FIG. 21.

FIG. 23 is a schematic illustration of a top view of an alternatereinforcing mat in accordance with the present invention.

FIG. 24 is a cross-sectional view of the reinforcing mat of FIG. 23.

FIG. 25 is a schematic illustration of a top view of an alternatereinforcing mat in accordance with the present invention.

FIG. 26 is a cross-sectional view of the reinforcing mat of FIG. 25.

FIG. 27 is a schematic illustration of a top view of an alternatereinforcing mat in accordance with the present invention.

FIG. 28 is a cross-sectional view of the reinforcing mat of FIG. 25.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 1A illustrate a pultruded part 10 for a fenestration productin accordance with the present invention. The part 10 is shown as ahollow, closed, pultruded body 12 having uniformly spaced outer wallstructure 14, an inner wall structure 16 and a resin matrix 20. Thereinforcing mat of the present invention is typically located at or nearwall structures 14 and 16 to increase transverse strength, althoughother configurations are possible (see FIG. 2A). In the embodiment ofFIGS. 1 and 1A, the pultruded part 10 is a window sash rail, althoughnumerous fenestration and non-fenstration products can be made using thepresent invention. As used herein, “fenestration products” refers towindows, doors, skylights, shutters, and components thereof, such as forexample window jambs, sills, heads, sash stiles, sash rails, doorthresholds, and the like.

FIG. 2 illustrates a portion of the pultruded part 10 and a reinforcingmat 18. Pultruded body 12 has wall structures 14 and 16 each includingthe reinforcing mat 18 located on opposite sides of the resin matrix 20.The resin matrix 20 includes longitudinally extending reinforcingfibers, referred to herein as longitudinal rovings 22. The rovings 22function to give the pultruded part 10 longitudinal strength andmodulus. A reinforcing mat 18 provides the pultrusion walls 14 and 16transverse strength to resist transverse forces “F” by locatingtransverse oriented reinforcing fibers in the part. The resin matrix 20preferably surrounds and impregnates the longitudinal rovings 22 and thereinforcing mat 18. A relatively thin layer 24 of the resin 20 coversthe outer face of each of the reinforcement mats 18 to provide thedesired surface characteristics. The resin matrix 20 preferablyimpregnates the reinforcing mat 18.

FIG. 2A illustrates an alternate wall structures 14A and 16A for apultruded part 10A in accordance with the present invention. Areinforcing mat 19A is located near the interior, rather than near thesurfaces. In the illustrated embodiment, one or more layers of rovings22A are positioned on both sides of reinforcing mats 18A and 19A. Thepultruded part 10A exhibits alternating layers of reinforcing mats 18A,19A and rovings 22A. A thin layer 24A of resin forms the surface of thewall structures 14A and 16A.

As illustrated in FIG. 2A, the layers of reinforcing mat and rovings canbe arranged in a variety of configurations and the present invention isnot limited to locating the reinforcing mat on an outer surface of thepultruded part. The present reinforcing mats 18 or 18A permit themanufacture of pultruded parts with wall thicknesses of about 0.10inches, and preferably about 0.06 inches and more preferably about 0.03inches or less.

The resin matrix 20 comprises about 20-40% of the cost of the pultrudedpart 10. Minimizing wall thickness minimizes resin cost. The thinreinforcing mat 18 with high transverse strength of the presentinvention permits a reduction in wall thickness without compromisingtransverse strength.

The present reinforcing mat typically has a compressed thickness ofabout 0.004 inches to about 0.020 inches. In another embodiment, thereinforcing mat has a compressed thickness of about 0.010 inches toabout 0.012 inches. Since the reinforcing mat can be made relativelythin with a low areal density and reinforcing fibers oriented in thetransverse direction, the present reinforcing mat can be used to makerelatively thin pultruded parts.

In some embodiments, pultruded parts may be manufactured using the thinreinforcing mats of the present invention in which the profile consistsof resin impregnated longitudinal rovings or reinforcing fibers totalinga thickness of about 0.019 inches, with a resin impregnated reinforcingmat layer about 0.010 inches thick on each sides of the rovings, for atotal wall thickness of about 0.039 inches or less. In anotherembodiment, the wall thickness is about 0.045 inches to about 0.025inches. The present reinforcing mat permits about a 33% reduction inwall thickness with the same or greater transverse strength thanpultruded parts reinforced with conventional continuous filament mats.Wall thickness of about 0.039 inches using the present reinforcing matshave demonstrated a transverse tensile strengths of about 20,000 psi.

As used herein, “reinforcing fiber” refers to a single filament such asa monofilament, or a grouping of a plurality of pliable, cohesivethreadlike filaments, including without limitation glass fibers, naturalfibers, carbon fibers, metal fibers (such as for example aluminum),ceramic fibers, synthetic or polymeric fibers, composite fibers (such asa polymeric matrix with a reinforcement of glass, natural materials,metal, ceramic, carbon, and/or synthetics components), or a combinationthereof. Although the Figures illustrate the reinforcing fibersschematically as a single entity or structure, each discrete reinforcingfiber illustrated herein can be interpreted as either a single filament,such as a monofilament, or a group of filaments. As used herein,“roving” refers to a plurality of reinforcing fibers. Rovings aretypically not twisted or kinked so that maximum longitudinal strength ismaintained.

FIG. 3 schematically illustrates a pultrusion system 111 suitable foruse with a reinforcing mat in accordance with the present invention. Oneor more reinforcing mats 18′, 18″ (referred to collectively as “18”) aredirected from source rolls 116, 140, respectively over illustratedrollers 118 and/or 120 to resin bath 122. The wetted reinforcing webs 18pass over roller 124 into the pultrusion die 54. A plurality oflongitudinal rovings 126 from source roll 128 passes over roller 130,through resin bath 132, and then over rollers 134, 136 and 138 into thedie 54. The pultrusion die 54 typically has a profile corresponding toor otherwise needed to form the cross-sectional shape of the pultrudedpart 12. The longitudinal fibers are typically 675-yield (about 675yards per pound), 450-yield, 250-yield, or 113-yield glass reinforcingfibers, although fibers with other yields or non-glass fibers can beused for some applications.

A variety of techniques well known to one skilled in the art such ascarding plates can be used to pre-form or pre-shape the rovings and thereinforcing mats 18 for pulling through the die 54. The reinforcing matsdescribed herein can be used in pultrusion processes using the sametechniques as are used for conventional mats. The rovings and thereinforcing mats are collated together for passage through the die butare generally not connected until unified by the setting resin. Inanother embodiment, the reinforcing mats 18 are attached to some of thelongitudinal rovings 126, such as by stitching, adhesives and otherattaching techniques. In yet another embodiment, the reinforcing mats 18can be trapped between layers of rovings, such as illustrated in FIG.2A. As the longitudinal rovings 126 are pulled through the die 54, themats 18 are pulled along. The reinforcing mat 18 can be shaped using thesame mechanisms used to position the longitudinal rovings 126 relativeto the die 54.

Prior to entering the die, the reinforcing mats 18 are preferably shapedto correspond generally with the profile of the die 54. Roll forminganalogous to those used in forming sheet metal and/or heat-settingtechniques can be used to shape the reinforcing mats 18. Other suitablemethods for shaping the mats 18 are disclosed in U.S. Pat. No.4,752,5134 (Rau et al.) and U.S. Pat. No. 5,055,242 (Vane).

Pulling mechanism 52, which for example may comprise a pair of opposingrollers, is operable to pull part 12 from a pultrusion die 54. Insteadof passing the longitudinal rovings 126 and the reinforcing mats 18through respective resin baths 122, 132, as shown schematically in FIG.3, resin may be applied to the reinforcing fiber and the reinforcingmats 18 using conventional resin-applying procedures that are well knownto those skilled in this art. Various techniques for making pultrudedparts are disclosed in U.S. Pat. No. 4,564,540 (Davies et al.); U.S.Pat. No. 4,752,513 (Rau et al.); U.S. Pat. No. 5,322,582 (Davies etal.); and U.S. Pat. No. 5,324,377 (Davies).

The positioning of the longitudinal rovings 126 and the reinforcing mats18 relative to the die 54 in FIG. 3 is purely schematic and may changedepending upon the desired position of the reinforcing mats 18 and thelongitudinal rovings 126. The reinforcing mats 18 and the longitudinalrovings 126 can be located anywhere in a pultruded part. For example, asillustrated in FIG. 2A, alternating layers of reinforcing mats 18A, 19Aand longitudinal rovings 126 can be located throughout the pultrudedpart 12. In some embodiments, the longitudinal rovings 126 may beclosest to the surface of the part, rather than the mat.

A conventional pultrusion resin formulation may be used for pultrudingpart 10. A typical formula may include, for example, a mixture ofthermoset polyester resin containing a reactive diluent such as styrene,along with a hardener, a catalyst, inorganic fillers, a suitable surfacemodifier, and a die lubricant. Suitable resins are disclosed in U.S.Pat. No. 4,752,513 (Rau et al.); U.S. Pat. No. 5,908,689 (Dana et al.);and U.S. Pat. No. 5,910,458 (Beer et al.). A commercially availablethermoset resin suitable for use in the present invention is availablefrom Resin Systems Incorporated located in Edmonton, Alberta under theproduct designation Version G. Other suitable suppliers may includeReichhold, Ashland, and Dow.

Thermosetting matrix materials useful in the present invention caninclude thermosetting polyesters, vinyl esters, epoxides, phenolics,aminoplasts, thermosetting polyurethanes, derivatives and mixturesthereof. Suitable thermosetting polyesters include the AROPOL productsthat are commercially available from Ashland Chemical Inc. of Columbus,Ohio. Examples of useful vinyl esters include DERAKANE.RTM. productssuch as DERAKANE.RTM. 470-45, which are commercially available from DowChemical USA of Midland, Mich. Examples of suitable commerciallyavailable epoxides are EPON.RTM. 826 and 828 epoxy resins, which areepoxy functional polyglycidyl ethers of bisphenol A prepared frombisphenol-A and epichlorohydrin and are commercially available fromShell Chemical.

Non-limiting examples of suitable phenolics include phenol-formaldehydefrom Monsanto of St. Louis, Mo., cellobond phenolic from Borden ofColumbus Ohio, and specific phenolic systems formulated for pultrusionfrom BP of Chicago Ill., Georgia Pacific of Atlanta Ga., and Inspec(Laporte Performance Chemicals) of Mount Olive N.J. RESIMENE 841melamine formaldehyde from Monsanto. Useful aminoplasts includeurea-formaldehyde and melamine formaldehyde. Suitable thermosettingpolyurethanes include Adiprene® PPDI-based polyurethane supplied byUniroyal Chemical Company, Inc. of Middlebury, Conn. and polyurethanesthat are available from Bayer of Pittsburg, Pa., Huntsman of Edmonton,Alberta, and other resin formulators such as E. I. du Pont de NemoursCo. of Wilmington Del. Other components which can be included with thethermosetting matrix material and reinforcing mat in a pultruded partare, for example, colorants or pigments, lubricants or process aids,ultraviolet light (UV) stabilizers, antioxidants, other fillers, andextenders.

The resin used in producing the pultrusion product can be filled withother materials, either at the longitudinal reinforcing fiber area, atthe surface mat areas, or both. Fillers are generally present in amountsranging from a trace amount to 30 percent, preferably 10 to 25 percentand most preferably 15 percent. The fillers may be any suitable fillerutilized by the art to fill a resin system of the type being produced.Fillers and pigments such as calcium carbonate, titanium dioxide,hydrated alumina, kaolin clay, silicon dioxide, carbon black and thelike may be used. Wood flour, recycled plastic grinds, metal grinds suchas Valimet H2 spherical aluminum powder or Hoeganaes Ancoorsteel 1000atomized steel powder, fly ash, or the like, can also be used toreinforce or fill the resin of the pultruded part, to obtain improvedmechanical properties, to improve aesthetics, to increase or decreasedensity, or to reduce cost. Wood-fibers may be employed to achieve anatural-wood color in the pultruded product, in addition to the enhancedstrength and lowered material cost.

FIGS. 4 and 5 illustrate one embodiment of a reinforcing mat 18A inaccordance with this invention. The reinforcing mat 18A includes aseries of separate, transversely spaced, reinforcing fibers 28 (alsoreferred to as transport fibers) comprising a first longitudinal layer30. In the illustrated embodiment, the first layer 30 is made up ofrelatively fine reinforcing fibers 28 extending longitudinally in the 0°or pull direction 29 of reinforcing mat 18A. These reinforcing fibers 28can be oriented in the range of 0° to about +/−20°, and preferably about+/−10°, and more preferably +/−5°. As used herein, the term “layer”refers to the schematic illustration of the various reinforcing fibersin the Figures and is not intended to limit the structure of the presentreinforcing mat.

A second set of spaced reinforcing fibers 32 comprising a transversesecond layer 34 extend at an angle of about 90° with respect to the pulldirection 29. Reinforcing fibers 32 are desirably positioned insubstantially directly side-by-side, non-overlapping, slightly spacedrelationship to form a blanket of fibers without substantial breakstherebetween. As used herein, “non-overlapping” refers to generallycoplanar fibers that do not extend over or cover one another. Each ofthe reinforcing fibers 32 preferably extend continuously across thewidth of reinforcing mat 18A from edge portion 43 to edge portion 45. Asused herein, “extend continuously” refers to a single strand ofreinforcing fiber running in an unbroken segment from one edge of areinforcing mat to another edge. The 90° orientation of the reinforcingfibers 32 maximizes the transverse strength and increased modulus of thepultruded part 10. In lieu of the preferred 90° orientation, thereinforcing fibers 32 may be positioned at other angularities within therange of about 90°+/−30° and more typically about 90°+/−20° (relative tothe 0° or pull direction 29) in the plane of the mat

In the illustrated embodiment, the reinforcing fibers 32 have asubstantially larger cross-sectional profile than the cross-sectionalprofile of each of the elongated reinforcing fibers 28, as is evidentfrom the schematic representations of FIGS. 4 and 5. In an embodimentwhere the transverse reinforcement fibers 32 extending in the 90°direction (+/−30°) are not overlapping (see e.g., FIGS. 4 and 5), theypreferably comprise at least 30%, and more preferably at least 40%, ofthe total volume of material comprising the reinforcing mat 18A. In anembodiment where the first reinforcing fibers 32 are overlapping (seee.g., FIGS. 27 and 28), the reinforcing fibers extending in the 90°direction (+/−30°) direction preferably comprise at least 40%, and morepreferably at least 50%, of the total volume of material comprising thereinforcing mat 18A. As used herein, the pull direction 29 is designated0°. The orientation of all other reinforcing fibers will be referencedfrom the pull direction 29. The pull direction 29, however, isindependent of the orientation of any particular reinforcing fiber. Thereinforcing mat 18 can be oriented in any direction for pulling throughthe pultrusion die, although some directions are preferred over other.For most applications, however, the larger reinforcing fibers 32 arepreferably oriented transverse from the pull direction 29. As usedherein, “transverse” refers to a direction generally perpendicular tothe 0° or longitudinal pull direction +/−30° , and typically +/−20°, ina plane of a reinforcing mat.

Angular reinforcing fibers 38 comprising an angular reinforcing layer 36extend at an angle of about 45° with respect to the pull direction 29.In the illustrated embodiment, the reinforcing layer 36 is locatedadjacent to the layer 34. The reinforcing fibers 38 shown in FIGS. 4 and5 have a smaller cross-sectional area as compared with thecross-sectional area of transverse reinforcing fibers 32.

Another angular reinforcing layer 40 is located adjacent to the layer36. The reinforcing fibers 42 are desirably at angle of about 45° withrespect to the 0° or the pull direction 29. The angularity ofreinforcing fibers 38 may be characterized as +45° while the angularityof reinforcing fibers 42 may be characterized as −45° both with respectto the 0° or the pull direction 29. The reinforcing fibers 38 and 42 ofangular layers 36 and 40 may be positioned in diagonal directions withinthe range of about +30° to about +60° and from about −30° to about −60°,respectively. The angular reinforcing fibers 38 and 42 operate, at leastin part, as transport fibers that provide longitudinal strength, shearstrength and skew resistance. As used herein, “transport fiber” refer tofibers that assist in maintaining the integrity of the reinforcing matas it is drawn through the pultrusion die.

The reinforcing fibers 38 of layer 36 and reinforcing fibers 40 of layer42, extending in opposite directions at 45° angles impart shear strengthto the reinforcing mat 18A. This increased shear strength isattributable to the fact that reinforcing fibers 38 of layer 36 andreinforcing fibers 42 of layer 40 transmit forces substantially equallyin the opposite directions to edge portions 43 and 45 of the mat. Byproviding such diagonally and oppositely oriented fibers at +45° and−45°, there is minimal tendency for one of the edge portions 43 or 45 tomove in advance of the other edge and thus a twisting or skewing thereinforcing mat during pultrusion of part 10. As used herein, “skew”refers to a change in the angular relationship of reinforcing fibers inthe plane of a reinforcing mat. Skew typically is exhibited by one sideedge of the reinforcing mat moving in advance of the other side edgeduring pultrusion.

The reinforcing fibers 38 and 42 are preferably continuous and extendacross the width of the reinforcing mat so as to maximize transmissionof forces in respective diagonal directions. The volume of reinforcingfibers in the layer 36 is preferably about the same as in the layer 40so that there is a generally uniform resistance to skewing and shearstrength stiffness modulus throughout the reinforcing mat 18A. Layer 30,in conjunction with layers 36 and 40, gives the reinforcing mat 18Adimensional stability in the 0° and +/−45° directions so that thereinforcing mat 18A can be bent to make pultruded parts with complexshapes, yet offer sufficient tracking consistency and necking-resistancefor consistent processing during pultrusion.

A permeable transport layer 44 is located adjacent to the layer 40,although one or more reinforcing layers 44 can be located between any ofthe layers 30, 34, 36, 40 of FIG. 5. In the illustrated embodiment, thepermeable transport layer 44 comprises a permeable transport webcomprising a plurality of relatively short staple fibers or cut fibers46. The permeable transport layer 44 is preferably made up of randomlyoriented staple or cut fibers of a length within the range of about 0.01to about 12″, and preferably in the range of about ½″ to about 4″. Thestaple fibers are preferably heat-fusible fibers. As used herein,“permeable transport web” refer to a plurality of staple fibersattachable to various reinforcing fibers in a reinforcing mat to providelongitudinal strength, shear strength and anti-skew properties. Prior toattachment to the reinforcing fibers, the staple fibers can be acollection of loosely associated fibers, a batting material, or avariety of other configurations. As will be discussed in detail below,in some embodiments the permeable transport web operates in combinationwith other transport components, such as binders, stitching fibers,adhesives, thermal bonding, various methods for entangling the staplefibers with the reinforcing fibers, diagonal reinforcing fibers (alsoreferred to as transport fibers), and the like.

A proportion of fibers 46 a are deflected from the plane of the layer 44to become randomly oriented, intertwined and entangled with thereinforcing fibers 28, 32, 38, 42. The staple fibers or cut fibers 46 aeffectively mechanically interconnect or attach the layers 30, 34, 36,40 and 44. The entangling fibers 46 a preferably extend substantiallythrough the thickness of reinforcing mat 18A and prevent the layers 30,34, 36, 40 and 44 from separating or moving one with respect to anotheras the reinforcing mat 18A is pulled through a pultrusion die 54. Thereinforcing layer 44 also maintains the relative position of therespective fibers 28, 32, 38, 42 in the reinforcing mat 18A.

In addition to interconnecting the layers 30, 34, 36, 40 and 44, thelayer 44 provides strength and resistance to skew in substantially alldirections. Additionally, while the layer 30 provides strength primarilyin about the 0° or pull direction 29, the fibers 28 will resist skewingforces at some angles other than 0°. Similarly, the fibers 32 willresist skewing forces at some angles other than 90° and the fibers 38,42 will resist skewing forces at angles other than +/−45°. It is thecombined effect of the reinforcing layer 44 and the various fiber layers30, 34,36, 40 that provide the present reinforcing mat 18 with theproperties that make it suitable for pultrusion.

The contributions of the fibers 28 and 42 in combination with thereinforcing layer 44 provides the reinforcing mat 18A with sufficientin-plane mechanical stability so that thin walled pultruded parts can bemade with minimal skewing of the reinforcing mat 18 and minimal shiftingof the relative position of fibers 28, 32, 38, 42. For a planarreinforcing structure, the phrase “in-plane mechanical stability” refersto a resistance to deformation and skew in the plane of the articlesufficient to use in a pultruded part having a non-planar profile.

In another embodiment, the layers 30, 34, 36, 40 and 44 can beinterconnected or attached by stitching with a fiber 47 using aconventional multi-head stitching machine used in the textile industry.It can be seen in FIGS. 4 and 5 that the fiber 47 pass through andinterconnect all of the layers 30, 34, 36 and 40 of reinforcing mat 18A.In another embodiment, the layer 44 can also be stitched to the otherlayers 30, 34, 36 and 40. In yet another embodiment, the firstreinforcing fibers 32 can be spaced apart and attached together bycontinuous fiber stitching 47.

In the embodiment illustrated in FIG. 5, the stitching fiber 47 wrapsaround some of the reinforcing fibers 32. In embodiments where thereinforcing fibers 32 are groupings of filaments, the stitching fiber 47can pass between individual filaments in the reinforcing fibers 32 (seee.g., FIG. 20).

The fiber 47 illustrated in FIGS. 4 and 5 are schematic only. By virtueof the flexibility of the individual stitches interconnecting layers 30,34, 36 and 40, the reinforcing mat remains highly flexible, althoughmechanically interconnected in a stabilized manner by the fiber 47. Thefiber 47 can be polyester thread, a natural fiber thread as for examplecotton, or a variety of other known materials.

In another embodiment, the layers 30, 34, 36,40 and 44 maybeinterconnected or attached using a variety of other techniques. As usedherein, “attach” refers to mechanical and or chemical techniques,including without limitation stitching, entangling strands of staplefibers or cut fibers intimately with the reinforcing fibers, thermalbonding, ultrasonic welding, adhesive bonding, conductive andnon-conductive binders, mechanical entanglement, hydraulic entanglement,vacuum compaction, or combinations thereof. Adhesive bonding includespressure sensitive adhesives, thermosetting or thermoplastic adhesives,radiation cured adhesives, adhesives activated by solvents, andcombinations thereof. Binders may also include a thermoplastic resinsheathing on certain or all of the reinforcing fibers, or such resinsheathing may if desired take the place of an added thermoplasticbinder. Suitable binders are disclosed in U.S. Pat. No. 4,752,513 (Rauet al.); U.S. Pat. No. 5,908,689 (Dana et al.); and U.S. Pat. No.5,910,458 (Beer et al.).

The present reinforcing mat 18A has a modulus of elasticity in thetransverse or 90° direction that is greater than the modulus ofelasticity in the 0° or pull direction. The ratio of the modulus ofelasticity in the transverse direction to the modulus of elasticity inthe 0° or pull direction is preferably at least 1.2, more preferably1.5, and still more preferably 3. In some embodiments the ratio is atleast 5. As used herein, “modulus of elasticity” refers to a ratio ofthe increment of some specified form of stress to some specified form ofstrain, such as Young's modulus, the bulk modulus, or the shear modulus.Modulus of elasticity can also be referred to as the coefficient ofelasticity, the elasticity modulus, or the elastic modulus. Modulus ofelasticity can be evaluated using ASTM D76-99 (Standard Specificationfor Tensile testing Machines for Textiles).

The present reinforcing mat can also be used for all other compositeprocesses, and is especially capable of high-strength, due to theoriented fibers, or reduced thickness, to decrease part cost or weight.The reinforcing mat can be used in composite spray-up parts, filamentwound parts, resin-transfer-molded parts, structural-reaction-injectionmolded parts, sheet-molding-compound parts, vacuum-bag parts, and othercomposite assemblies, to achieve a thin wall, low cost, low weight, highstrength, or the like. The process of using this reinforcing mat wouldbe similar to the current technologies of process, but thinner parts, ormultiple-mat thickness parts would be produced, as could be understoodby those skilled in these arts.

FIGS. 6-8 illustrate an alternate reinforcing mat 18B in accordance withthe present invention. The reinforcing mat 18B has a 0° layer 30′ madeup of a series of longitudinally extending reinforcing fibers 28′. Thelayer 30′ is adjacent to transverse layer 34′ made up of a series ofside-by-side reinforcing fibers 32′. Angular fiber layers 36′ and 40′made up of reinforcing fibers 38′ and 42′, respectively, are located onopposite faces of the 0° reinforcing fiber layer 30′ and 90° transversereinforcing fiber layer 34′, respectively, as best shown in FIGS. 6 and7. The diagonally oriented reinforcing fibers 42 and 38 may have anangularity of about +/−45° to angles within the range of about +/−30° toabout +/−60°. Permeable transport layer 44′ is positioned in overlyingrelationship to the outer face of angular reinforcing fiber layer 36′.The layer 44′ comprises a series of relatively short staple fibers 46′with the entangled connecting fibers being designated by the numeral 46a′.

FIGS. 11-13 illustrate a precursor web before the addition of apermeable transport layer. Two longitudinally extending reinforcinglayers 144 and 146 are provided on opposite sides of centrally located,substantially larger reinforcing fibers in transverse layer 148. Twoangular reinforcing layers 150 and 152 are positioned against the faceof longitudinal layer 144 opposite transverse layer 148. The angularreinforcing layers 150 and 152 are preferably oriented in oppositediagonal directions at about 45° with respect to the longitudinal lengthof the mat. FIG. 14 illustrates a reinforcing mat 18C made from theprecursor structure of FIG. 13. A permeable transport layer 154 ispositioned on top of the diagonal reinforcing fiber layer 150. Therelatively short fibers of the permeable transport layer 154 areschematically shown as being entangled with the layers 144, 146, 148,150, 152.

FIGS. 15-16 illustrate a reinforcing mat 18D in which diagonalreinforcing fibers 160 and 162 are positioned at 70° angles with respect0° or the pull direction 29. The layers 164 and 166 are located onopposite sides of the layer 168 containing the transverse reinforcingfibers 170. The permeable transport layer 172 interconnects or attachesthe layers 164, 166, 168, and 172. The diagonal reinforcing fibers 160,162 provide adequate dimensional stability in the pull direction 29 sothat the 0° reinforcing fibers can be omitted.

FIGS. 19-20 illustrate another embodiment of a reinforcing mat 18E inaccordance with the present invention. The reinforcing mat 18E includesa series of elongated, separate, essentially parallel, spaced,transverse reinforcing fibers 220 arranged to form a transversereinforcing layer 222. The reinforcing fibers 220 of reinforcing layer222 are oriented at an angle of approximately 90° with respect to 0° orthe pull direction 29 of a part through the die 54. The reinforcingfibers 220 are laid continuously across with width of the reinforcingmat 18E and lie in a slightly spaced, side-by-side relationship. Aspreviously explained, transversely oriented reinforcing fibers increasethe modulus of a pultruded part 10 reinforced with reinforcing mat 18E.Although reinforcing fibers 220 illustrated at 90° in FIG. 19, thereinforcing fibers 220 may be positioned at other angularities withinthe range from about 60° to about 120° in the plane of the mat. Also aspreviously indicated, transverse fiber reinforcing fibers 220 normallyare present in an amount within the range of about 40% to about 90% ofthe total volume of material comprising the reinforcing mat 18E.

Mat 18E also has two layers 224, 226 of angled reinforcing fibers 228,230, respectively. As is most evident from FIG. 19, the reinforcingfibers 228 of layer 224 are at an angle of about +45° with respect to 0°while the reinforcing fibers 230 of layer 226 are at an angle of about−45°. The reinforcing fibers 228, 230 of layers 224, 226 are of a lesserdiameter than the diameter of individual transverse reinforcing fibers220 in order to maintain the as much of the volume of the reinforcingmat 18E in the transverse or 90° direction.

The layers 224, 226, 228 are interconnected or attached by spaced,parallel individual lines of stitching 232. In the embodiment of FIG.19, the reinforcing fibers 220 are typically groups of filaments throughwhich the stitching 232 can pass. From FIG. 19 it can be seen that thelines of stitching 232 extend in perpendicular relationship toreinforcing fibers 220. Each line of stitching 232 is made up of arelatively straight bobbin thread 234 and a serpentine stitch thread236. The bobbin thread 234 of each line of stitching 232 generally laysin underlying relationship to the reinforcing fibers 220, while thestitch thread 236 of each line of stitching 232 extends into overlyingrelationship to the layer 224 of reinforcing mat 18E, thus serving tointerconnect layers 222, 224, 226. As used herein, a “stitched thread”is located on a front surface of a reinforcing mat and a “bobbin thread”is located on the opposite side of the mat.

It is also to be observed from FIG. 19 that the upper right segments 236of adjacent stitch threads 236 are offset from one another in adirection perpendicular to reinforcing fibers 220. The lines ofstitching are applied using a multiplicity of adjacent, mutuallycooperative, individual stitching heads as previously herein. Althoughpolyester thread is preferred for lines of stitching 232, other commonmaterials may be used such as cotton thread or other natural orsynthetic resin fibers, depending upon the pultrusion process, themechanical properties desired of for example a pultruded fenestrationproduct, or other pultruded part.

A permeable transport layer 238 is provided in overlying relationship tolayer 224. The permeable layer 238 is preferably made up of randomlyoriented staple fibers. At least a certain proportion of the staplefibers are entangling fibers 240 that randomly extend through at least apart of the composite thickness of reinforcing mat 18 and serve tofurther interconnect the individual layers 222, 224, 226, 238 ofreinforcing mat 18 in conjunction with the lines of stitching 232.

The entangling fibers 240 are preferably hydro-entangled with layers222, 224, 226 utilizing hydro-entanglement equipment and employingprocedures as described herein. The closely spaced heads of thehydro-entangler divert staple fibers from the plane of the layer 238thereby causing hydro-jet diverted staple fibers to extend randomly in adirection through the thickness of the composite mat 18E. To that end,the staple fibers making up reinforcing mat 18E preferably have arelatively low resistance to bending so that randomly oriented fibersare forced downwardly into and through the layers of the reinforcing matbelow using hydro-entangling equipment.

FIGS. 21 and 22 illustrate an alternate the reinforcing mat 18F similarto that illustrated in FIGS. 19 and 20, except that the layers 322, 324,326 and 328 are attached without stitching. Transverse reinforcingfibers 320 are arranged at 90° to the pull direction 29. Two angledreinforcing layers 324, 326 of angled reinforcing fibers 332, 334oriented at about +/−45° are positioned between the layer 322 and thepermeable transport layer 328. Fibers 330 from the layer 328 extendthroughout the thickness of the reinforcing mat 18F to form a mechanicalbond between the layers 322, 324, 326, 328. Supplemental holes 336 areformed in the permeable layer 328 to facilitate wetting of thereinforcing mat 18F with resin during the pultrusion process. Secondaryattaching techniques may also be used, such as the addition of bindersand/or adhesives, thermal bonding, and the like.

FIGS. 23 and 24 illustrate an alternate reinforcing mat 18G in which thelayer 352 of reinforcing fibers 354 arranged at 90° from the pulldirection are stitching 356. The first reinforcing fibers 354 arepreferably spaced apart and attached together by continuous fiberstitching 356. The stitching 356 holds the reinforcing fibers 354 in anarray during attachment of permeable transport layer 358. The permeabletransport layer 358 is provided on at least one side of the layer 352.Staple fibers 360 of layer 358 are entangled with the reinforcing fibers354 of transverse reinforcement layer 352 to form a reinforcing mat within-plane mechanical stability. Supplemental holes 362 are formed in thepermeable layer 358 to facilitate wetting of the reinforcing mat 18Fwith resin during the pultrusion process.

In another embodiment, the array of transverse reinforcing fibers 354and the permeable transport layer 358 are stitched together to form acombined structure. The stitching is preferably applied after hydraulicentanglement and heat fusing of the transverse reinforcing fibers 354 tothe permeable transport layer 358.

FIGS. 25 and 26 illustrate an alternate reinforcing mat 18H having alayer 402 of transverse reinforcing fibers 404 arranged at about 90°relative to the pull direction 29. A permeable transport layer 406 ispositioned on one side of the layer 402. Staple fibers 408 of the layer406 are entangled with the layer 402 to form a reinforcing mat 400 within-plane mechanical stability. Supplemental holes 410 are formed in thelayer 406 to facilitate wetting during pultrusion. In addition to theentangled staple fibers 408, other techniques disclosed herein may alsobe used to attach the layer 402 to the layer 406, such as thermal oradhesive bonding, binders, stitching and the like. In one embodiment, asecond permeable transport layer 412 is optionally located on the otherside of the layer 402. Fibers 414 from the layer 412 also entangle withfibers 408 from the layer 406. The second layer 412 reinforces thereinforcing mat 18H, particularly if the layers 406 and 412 arethermally bonded.

FIGS. 27 and 28 illustrate an alternate reinforcing mat 181 having twolayers 420, 422 of transverse-acting reinforcing fibers 424, 426,respectively. The transverse-acting reinforcing fibers 424, 426 have asubstantially larger cross section, corresponding generally to thetransverse reinforcing fibers 32 in FIG. 5. In one embodiment, thereinforcing fibers 424 are arranged at about 60° (+/−15°) relative tothe pull direction 29. The reinforcing fibers 424 are desirablypositioned in substantially directly side-by-side, non-overlapping,slightly spaced relationship. The reinforcing fibers 426 are arranged atabout −60° (+/−15°) relative to the pull direction 29. The reinforcingfibers 426 also do not overlap with each other. The layers 420, 422,however, do overlap. As used herein, “overlap” refers to fibers thatextend over or cover one another.

In another embodiment, the reinforcing fibers 424, 426 are arranged at45° and −45° (+/−15°), respectively. While the orientation of the fibers424, 426 in these two embodiments are outside the definition of“transverse”, arranging the reinforcing fibers 424, 426 at opposingangles in these ranges is desirable for some applications. In bothembodiments, the reinforcing fibers 424, 426 preferably comprises atleast 30% of a volume of materials comprising the reinforcing mat 181,and more preferably 40%.

A first permeable transport layer 430 is positioned on one side of thelayers 420, 422. Staple fibers 432 of the layer 430 are entangled withthe layers 420, 422 to form a reinforcing mat 181 with in-planemechanical stability. Supplemental holes 434 are formed in the layer 430to facilitate wetting during pultrusion. In one embodiment, a secondpermeable transport layer 436 is optionally located on the other side ofthe layers 420, 422. Fibers 432 from the layer 436 also entangle withfibers 424, 426. The second layer 436 reinforces the reinforcing mat181, particularly if the layers 430, 426 are thermally bonded. Inanother embodiment, an additional layer of reinforcing fibers isprovided in the 0° direction to enhance pulling strength (see FIG. 4).

Method of Making a Reinforcing Mat

FIG. 9 illustrates an apparatus 78 for making the reinforcing mat 18 inaccordance with the present invention. The apparatus 78 includes aconveyor belt 80 arranged to carry the components of the reinforcing mat18 from an initial supply to a wind-up device 82. The longitudinallength 84 of the belt corresponds to the 0° direction of the reinforcingmat 18 during manufacturing.

A precursor web 85 is made by sequentially laying onto the belt 80 aplurality of reinforcing fibers from supply units 86, 88, 90, and 92. Aplurality of needles are preferably located along the edges of the belt80. Supply head 90 continuously lays down reinforcing fibers along thelongitudinal length of belt 80, thus providing a 0° lay of reinforcingfibers. Reinforcing fibers supply head 88 is operable to reciprocateback and forth across the width of belt 80 to lay down 90° transversereinforcing fibers. The reinforcing fibers are wound around needlesalong each edge of the endless belt 80 to arrange the reinforcing fibersfor the desired orientations.

Angled reinforcing fiber supply head 92 lays down a reinforcing fiberson the previously applied 0° and 90° reinforcing fibers at about a 45°angle. Diagonal reinforcing fiber supply head 86 functions to lay downreinforcing fibers at an angle of about −45° with respect to thelongitudinal length 84 of the belt 80. The head 86 traverses back andforth across belt 80 in timed relationship to the speed of the belt 80to provide angled reinforcing fibers. The angled reinforcing fibers arewound around the needles along each edge of the endless belt 80.Preferred results have been obtained by using 11 courses per inch of 90°reinforcing fiber, about 8 courses per inch of 45° angular reinforcingfibers, and about 8 courses per inch of 0° reinforcing fibers in anassembled web 18.

The present method permits the combination of 0°, 90°and +/−45°reinforcing fibers to be varied. For example, the 0° fibers can beeliminated to make a reinforcing mat similar to that illustrated inFIGS. 15 and 16. In another embodiment, only the 90° reinforcing fibersare applied, such as illustrated in FIGS. 25 and 26. Various methods fordepositing the layers of reinforcing fibers are disclosed in U.S. Pat.No. 4,484,459 (Hutson); U.S. Pat. No. 4,550,045 (Hutson); U.S. Pat. No.4,677,831 (Wunner); and U.S. Pat. No. 5,308,424 (Sasaki et al.).

In one embodiment, a plurality of stitching heads 94 are provided downstream of the supply units 86, 88, 90, 92. The stitching heads 94optionally form spaced, parallel lines of stitching in the layers ofreinforcing fibers (see e.g., FIG. 20). The stitch thread can bepolyester, aramid thread for toughness, natural fibers for cost,polyamides, such as Pegaso Micro Helanfil 2×80 dtex or HoneywellAnso-tex nylon, for resilience, or carbon threads for stiffness orhigh-temperature capability. A suitable assembly for depositing thelayers of reinforcing fibers and stitching the layers together isavailable from LIBA Maschinenfabrik GmbH of Germany under the tradedesignation Centra Max 3 CNC fiber inserter.

In another embodiment, the stitching is omitted and the web 85 is passedunder a hot roll 98 to assist in bonding of the layers of the web 85 oneto another. The use of hot roll 98 is particularly suited when one ormore of the reinforcing fibers contain a polymeric component. The roll98 act also to calender the web 85 so that it is compressed and slightlyreduced in thickness. The temperature of the roll 98 is preferablyselected to cause the minimal amount of softening of the polymericcontent and still achieve an adequate bond between the fibers. The roll98 may also bond the polymeric components of the reinforcing fibers byimparting ultrasonic energy. In another embodiment, the heat is omittedand a simple calendering action is used.

Non-woven machine 100 deposits polymeric cut-staple fibers onto the web85. The non-woven machine 100 can be a variety of structures, such asfor example an air lay machine or a mechanical card. The staple fibersare the precursor material for making the permeable transport layerdiscussed herein. The staple fibers are typically blended and carded,and a predetermined thickness is achieved by stacking a plurality oflayers of staple-fiber webs or batting onto the web 85.

In one embodiment, the staple fibers comprise a non-woven batting webmay be made by blending of polyester staple fibers. The staple fiberspreferably include a portion of high melt fibers and a portion of lowmelt fibers. In another embodiment, the low melt fibers are abi-component fiber with a high melt portion and a low melt portion. Thelow melt portion provides a bonding function with the various layers,while the high melt portion minimizes warping and shrinkage of thereinforcing mat 18 and excessive flow of the low melt polymer. Apreferred bi-component fiber is a core-sheath configuration with the lowmelt polymer on the sheath and the high melt polymer at the core. In oneembodiment, the high melt fibers have a glass transition temperature ofabout 350° F. and the low melt fibers have a glass transitiontemperature of about 270° F.

In another embodiment, the non-woven machine 100 may include spinningneedles that convert an open fiber polymeric material into high loft“tufts” of non-woven fibers. The tufts of high loft material aredeposited in an accumulator until a target weight is reached, whereuponthe tufts are dropped onto the web 85. When more than one type of openfiber polymeric material is used, separate accumulators are used so thatthe percentage of each type of material can be independently controlled.

In one embodiment, the staple fibers are blended and opened in anon-woven opener sold under the product referred to as a carding machineor garnet wheel sold by Sigma Fiber Controls of Simpsonville, S.C. Thestaple fibers and/or cut fibers are then fed through a Rando webber sothat a density of about 32 gram/meter² to about 60 gram/meter² isreached. The Rando feed and doff speeds are set to achieve the desireddensity. One or more layers of the non-woven batting is then depositedon the web 85.

After the staple fibers are laid onto the web 85, they are entangledwith the layers of reinforcing fibers. In the illustrated embodiment,the staple fibers are entangled using a water-jet hydro-entangler 66,such as the structure illustrated in FIG. 10. The hydro-entangler 66substantially compresses the staple fibers to achieve the overallreinforcing mat thickness of about 0.004 inches to about 0.020 inches.The individual jets of water wet the randomly oriented fibers of thestaple fibers directly to the reinforcing fibers and force certain ofthe fibers into locations extending throughout the reinforcing mat 18.In some circumstances the water jets from the hydro-entangler unit maybreak up some of the fibers of the reinforcing fibers to produce shortentangling fibers randomly oriented in the same manner as entanglingstaple fibers. These broken reinforcing fibers may extend throughout thecross-section of the web 18. These broken reinforcing fibers cooperatewith the staple fibers to maintain the layers in proper relativerelationship during processing of reinforcing mat 18 and in the usethereof as a reinforcement for a pultruded part.

Turning now to FIG. 10, the web 85 with multiple layers of reinforcingfibers 71A, 71B, 71C, 71D and the layer of staple fibers 73 is fed intoa hydro-entangler 66 on a fine-mesh belt 76. In general, thehydro-entangler 66 has upper manifold structure 68 receiving water fromsupply source 70 provided with a plurality of openings or nozzles 72which direct water jets 74 directly onto the web. The water-jetsdelivered from nozzles 72 are preferably pulsed so that the jet streamsexit through respective nozzles 72 and pass through the thickness of theweb 85 until impacting the upper surface of a fine mesh belt 76. Thewater streams impacting against the upper surface of belt 76 cause thewater to dissipate and thereby spread the fibers carried by the jetstreams transversely across the top of the belt 76 to enhanceentanglement of the web 85.

A suitable hydro-entangler is commercially available from ICBT Perfojetof Mont Bonnet, France. The ICBT Perfojet hydro-entangler has threehorizontally-spaced manifolds of the type shown schematically in FIG.10, each having a row of water-jet nozzles 68, with the nozzles spacedat approximately eight per inch, providing a total of 100 to 150 nozzleopenings. The water is jetted onto the web 85 with the first manifoldset at a water pressure of 500 psig, the second at 1500 psig, and thethird at 1500 psig. The web 85 becomes entangled as the water jets frommanifold 66 pass through the layered material making up the reinforcingmat 18. The hydro-entangler has the capability to blow-in holes orenhance existing holes in the web 85 to achieve higher permeability.Permeability is useful to allow resin to flow through the thickness ofthe reinforcing mat in the pultrusion die, to avoid harmful hydraulicsor bubbling of the reinforcing mat at the pultrusion die entrance. Whenenhanced by hydro-entangling, the hole size and distribution aredetermined by the hydro-entangler back screen pattern and back screenmesh size.

A mesh size of 24×48 wires/inch in the backside conveyor belt thattransports the web 85 through the hydro-entangling process has been usedto create an array of holes 24×48 holes/inch², to increase thepermeability. A mesh size of 10×10 wires/inch can also be used for someapplications where the coarses mesh allows for larger holes,corresponding to a higher and more desirable permeability.

A permeability of 200-400 ft³/minute/ft² of air, through the web 85 (ata pressure differential of 0.5″ of water) is sufficient for the resin topenetrate the reinforcing mat 18 during pultrusion, but a permeabilityof 600-800 ft³/minute/ft² or higher works very well for subsequentpultrusion processing. In an alternate embodiment, the hole size anddistribution is enhanced by a needling operation.

In lieu of using a hydro-entangler as described, a head (notillustrated) may be provided which supports a series of barbed needles142 as shown in FIG. 18. In this case, the layer of staple fibers 73should be opposite the points 142 a of the needles so that when thebarbed needle penetrate the mat, the barbs 142 b do not engage thefibers of the staple fibers 73. However, upon retraction of the barbedneedles 142, the barbs 142 b thereon engage certain of the relativelyshort fibers and pull all at least a portion of such fibers upwardlyinto the reinforcing fiber layers and to entangle the staple fibers withthe reinforcing layers.

Turning back to FIG. 9, the web 85 can optionally be fed into a needleror perforator 108 that has a head 110 which supports a plurality ofparallel, relatively closely-spaced needles 112 (FIG. 17) locateddownstream of the hot rolls 106. The head 110 is reciprocated tosequentially direct the needles 112 through the reinforcing mat to forman array of perforations. The array includes perforations spaced bothlongitudinal and transversely so the series of needles across the widthof the web 85 are punched through the web 85 as it moves forwardly toprovide the required number of spaced perforations. The perforationsincrease the porous nature of the reinforcing mat 18 and allowpenetration of resin to bond through the reinforcing mat into thevarious components of the mat.

From 1 to about 5000 holes per square inch may be formed in the webusing perforator 108, but about 80 holes per square inch formed by #14needle size is preferred in a rectangular grid pattern. The needler 108may be of conventional design which functions at a rate of approximately20 cycles or reciprocations per second. The holes may be round orpolygonal and generally are of a diameter what may be characterized aspin holes. The hole pattern may be random, square, rectangular,close-packed-hexagonal, or similar configurations. During needling, theneedles can optionally be heated to about 160° F., by use of electricheat guns placed inside the needle box area, and blowing air through thelength of the needle board.

The flow of viscous resin (such as polyester resin) through thereinforcing mat during the pultrusion process affects the speed ofpultrusion and the quality of the pultruded part. The permeability ofthe reinforcing mat is particularly important at the die entrance forboth a bath style and a resin-injection style of pultrusion.

Permeability is measured using the procedures disclosed in ASTM D737-96Test Method for Air Permeability of Textile Fabrics, which isincorporated herein by references. The rate of air flow passingperpendicularly through a known area of fabric is adjusted to obtain aprescribed air pressure differential between the two fabric surfaces.From this rate of air flow, the air permeability of the fabric isdetermined. The pressure differential used was 0.5 inch column of water.

Reinforcement fiber mats which are parallel to the direction ofpultrusion typically have a permeability of at least about 180ft³/minute/ft². To obtain pultrusion speeds with 30% filler in theresin, permeability of 300-350 ft³/minute/ft² is preferred. Apermeability of about 300-350 ft³/minute/ft² can be achieved by using acoarse mesh entangler-belt in the hydro-entangler, so that a smallernumber of larger holes are created (in the range of about 50 holes persquare inch) to maximize the capability of polyester resin flow throughthe mat. For some applications, reinforcing mats with a permeabilityabove 350 ft³/minute/ft² meets can be used.

The web 85 is directed under a vacuum system 87 that draws most of thewater from the web 85. The substantially dried web 85 is then passedthrough a forced-air oven 89. The oven 89 is preferably operated at atemperature between the glass transition temperature of the low melt andhigh melt staple fibers. The staple fibers preferably soften and bond,but do not flow sufficiently to reduce the permeability of thereinforcing mat 18.

In an alternate embodiment, the web 85 is passes between a pair of hotrolls 106 which act to further calender the reinforcing mat and also tomelt and activate the polyester fibers to provide a bonding action. Inone embodiment, the rolls 106 are smooth 12 inch diameter smooth rollson a B.F. Perkins calender set at 120° C. with a minimum gap of 0.007inches. The rolls 106 reduce the reinforcing mat thickness and fuse thepolyester material into the reinforcing mat 18.

A binder or an equivalent powdered, solvent, thermal or aqueous basedthermoplastic binder is optionally applied to the reinforcing mat 18 bydispenser 113. The web picks up this binder, and is then squeezedthrough the rubber drying rolls 115 set at 30 psi, at the given speedper the needling process. Various binder materials can be applied to thereinforcing mat 18 to increase stiffness, such as corn starch, polyvinylacetate or similar binder material. In one embodiment, the bindermaterial is a reactive modified latex binder applied to the top surfaceof the reinforcing mat by an applicator which fills the intersticesbetween the layers of the mat.

Binder is applied at a concentration adequate to impart the desiredstiffness to the reinforcing mat for pultrusion handling and processing.The dry-mat stiffness may be tailored for ease-of-processing. Thereactive sites in the binder regulate the occurrence of cross-linkingwithin the binder upon drying, which renders those sited useless for thepurpose of enhancing the strength of the pultrusion. Although a 10%reactive solution of Franklin Duracet X080 binder has been found to bebeneficial and therefore preferred for enhancement of productionstrength, the level of binder reactive activity may be varied to achieveparticular processing strengths and product strengths desirable forparticular products.

An adhesive binding material such as polyvinyl acetate in a watercarrier and containing about 20% to about 60% solids, corn starch orother adhesive material can be used to assist in interconnecting thestructure so that the entangled fibers are bonded to the fibers of thereinforcing layers and the fibers are bonded to each other. Generally,the binding agent is present in an amount in the range of 2% to 20% byweight (dry weight without water). However, the amount of binding agentis significantly reduced relative to conventional non-woven mats andthus the stiffness of the structure is very much reduced and thereforeimproved, allowing the reinforcing mat to bend to take up the complexshape of the part to be formed while restricting shear.

If the staple fibers and/or some of the reinforcing fibers have athermoplastic content, the binder can be reduced or omitted. Instead,the fibers are heated to provide some amount of heat bonding to eachother. In the arrangement shown in FIG. 9, some of the entangling fibersare of a high melting point so that they remain intact and thus act asentangling fibers, and some are of a lower melting point so that theyact as bonding fibers. In some embodiments where the binder is notrequired for structural purposes, it may still be used to increasestiffness.

The reinforcing mat passes through drying oven 114 that uses 200° F. airforced through the thickness to dry the mat. A suitable drying oven isavailable from National Drying of Cary, NC. Once dried, the finishedreinforcing mat 18 is stored on roll 82. The reinforcing mat 18 canoptionally be slit longitudinally to the desired width for pultrusionprior to storage on the roll 82.

The calendering, needling, and padding steps can be rearranged,processed multiple times, or omitted if the reinforcing layers arethermally bonded with a resin as explained in detail herein, dependingon the desired permeability, stiffness, and thickness required for themat, to optimize the pultrusion process, and the mechanical propertiesof the pultruded product. The reinforcing mat formation may also becarried out on-line with the pultrusion process so as to avoid thewinding and supply steps although in general this is unlikely to bepractical in many circumstances due to the different speeds of theprocessing lines.

The reinforcing mat 18 as described provides reinforcement which hassufficient structural strength in the longitudinal and shear directionsto ensure that it will be transported through the pultrusion die withoutsignificant longitudinal deformation or skewing. This is attributable tothe fact that the main bulk of the fibers are arranged in the transversedirection to provide the finished product with the required transversestrength. The number of fibers therefore necessary for a predeterminedtransverse strength is significantly reduced since the bulk of thefibers are arranged in the direction to maximize the strength providedby each fiber.

Reinforcing mats of varying weight per square yard may be fabricated inaccordance with the present invention. Mats of 0.5-1.0 ounces per squareyard are useful for structural pultrusions with wall thickness of about0.038 inches to unusually-high-strength pultrusions that are 0.090″thick, although other sizes of reinforcing mat and pultrusions can bemade using this technology. The internal integrity of the presentreinforcing mat permit strips as small as 0.5 inches wide to be slitwithout causing the reinforcing layers to delaminate.

For example, if G-150 yarns are used as the reinforcement layer, then apultrusion wall thickness of 0.031″ or less is feasible while retainingthe required capability of a structural part having longitudinalstrengths of approximately 40,000 psi, and transverse strengths ofapproximately 20,000 psi. On the other hand, much thicker glass fibersmay be used to make thicker pultrusions with unusual high-strength, dueto the orderliness of the fiber orientation in the transverse direction.

In addition, multiple layers of the reinforcing mat are useful in theproduction of high-strength products, to achieve enhanced physicalcapability in the pultruded parts, by use of this technology. Forexample, if two or three layers of the mats are used in a regularstructural pultrusion that is 0.25-inches thick, then the strength ofthe pultrusion can be increased in the transverse direction as much as200-400%. The transverse stiffness of the thick pultrusion may also beadjusted by a factor of 200-400%, thereby enhancing the longitudinalcapability of the pultrusion because the bucking strength of thecomposite pultruded profile is dramatically increased.

In addition, one side of a pultrusion may be provided with multiplereinforcing mat layers, or a thick reinforcing mat may be employed onthe compression side of the pultrusion product, while the other side ofthe pultrusion may be provided with a single layer on the tensile side.In the case of a hollow or channel-profile pultrusion, the outside ofthe part may be provided with a single or thin mat, while the inside ofthe pultruded part is provided with thicker or multiple layers of thereinforcement mats.

The stacking sequence of the layers of the reinforcing mat may also bevaried to achieve the different or enhanced capabilities. For example,in lieu of the sequence of layers of the preferred embodiment ofreinforcing mat construction as illustrated in FIGS. 19 and 20, thepermeable transport layer may be located against the outer face of thetransverse glass reinforcing fibers, between the transverse reinforcingfibers and an adjacent transport layer, or between the oppositelyinclined rovings.

Reinforcing Fibers

The reinforcing fibers and the longitudinal rovings are preferablycompatible with the resin matrix. As used herein, the phrase“compatible” in the context of a thermosetting resin or matrix refers tofibers and other components of a pultrusion laminate or part areselected or treated so that they facilitate penetration and essentiallycomplete wetting and impregnation of the fiber and component surfaces bythe thermosetting resin or matrix material, provide desired physicalproperties of the cured or finished laminate or part, are chemicallystable with the thermosetting resin or matrix material and are resistantto hydrolysis.

The primary reinforcing fiber and the longitudinal rovings used inpultrusion are typically glass fibers. The 90° reinforcing fibers arepreferably a 900 yield E-glass fiber that has been treated with anorgano-silane composition to increase reinforcement-matrix interfacialstrength. The +/−45° oriented reinforcing fibers and the 0° directionreinforcing fibers are preferably G150's (15000 yards per pound) with athermoplastic polyester resin sheathing available from Engineered YarnsIncorporated of Fall River, Mass.

Glass reinforcing fibers can be replaced with carbon fibers to achievehigher stiffness, strength, or temperature capability. Graphite fibersmay for example be Mitsubishi Pitch K13C2U, Hexcel PAN AS4, and AmocoPAN T300. Glass reinforcing fibers can also be replaced with aramidfibers for toughness or resilience, using for example Teijin Technora orKevlar type aramid fibers, with Kevlar type 29 being useful and Kevlartype 49 being preferred. Polyester fibers may be substituted for glassfibers where extended elongation or toughness are requisite properties,or natural fibers (e.g. cotton, jute, hemp) for cost. Metal and ceramicfibers may also be used.

The reinforcing fibers may be enhanced to improve the capability of themat, or to tailor the reinforcing mat to achieve improved performance,including changes in geometry, stacking, materials, surface treatmentssuch as sizings, and binders. For example, the 0° reinforcing fibers andthe +/−45° reinforcing fibers may be pre-coated with a thermoplasticsynthetic resin comprising an amide, a polyester, or a similarsheath-like binder. When subjected to elevated temperature, thesheathing binder flows and thereby fuses the reinforcing fibers of allof the layers of the reinforcing mat together, thereby producing awindable pre-mat. In addition, acrylic, polyvinyl acetatec, or similaremulsions with cross-linkable sites may be deposited on thereinforcement fibers so that these fibers react in the pultrusioncomposite to enhance the mechanical properties of the reinforcing mat byreinforcement of the fiber/resin interface. Methods of making a coatedreinforcing fiber are disclosed in U.S. Pat. No. 4,058,581 (Park).

Enhancement of the glass fibers may be accomplished by addition of asurface treatment including an organosilane to the fiber surface toaugment the strength and durability of the final pultruded product. Theaddition of a coupling agent such as an organosilanes has been found toincrease the pultruded product physical properties, such as wet strengthretention. For example, application of an organosilane to G75 glassfiber yarns used for the transport fibers results in a stronger and moredurable pultruded product. When an organosilane coating is added to thereinforcing fibers, improved results were obtained when a cationicamino-functional silane. Tris(2-methoxyethoxyvinylsilane) and3-methacrylopropyltrimethoxysilane are exemplary silanes.

The composition for treating preferably comprises a surface treatmentcontaining one or more coupling agents selected from the groupconsisting of organo silane coupling agents, transition metal couplingagents, amino-containing Werner coupling agents and mixtures thereof.These coupling agents typically have dual functionality. Each metal orsilicon atom has attached to it one or more groups which can react withthe glass fiber surface and/or the components of the treatingcomposition. As used herein, the term “react” with respect to couplingagents refers to groups that are chemically attracted, but notnecessarily chemically bonded, to the glass fiber surface and/or thecomponents of the treating composition, for example by polar, wetting orsolvation forces. Examples of suitable compatibilizing or functionalgroups include epoxy, glycidoxy, mercapto, cyano, allyl, alkyl,urethano, halo, isocyanato, ureido, imidazolinyl, vinyl, acrylato,methacrylato, amino or polyamino groups.

Functional organo silane coupling agents are preferred for use in thepresent invention. Examples of suitable functional organo silanecoupling agents include A-187 gamma-glycidoxypropyltrimethoxysilane,A-174 gamma-methacryloxypropyltrimethoxysilane and A-1100gamma-aminopropyltriethoxysilane silane coupling agents, each of whichare commercially available from OSi Specialties, Inc. of Tarrytown, N.Y.The organo silane coupling agent can be at least partially hydrolyzedwith water prior to application to the glass fibers, preferably at abouta 1:3 stoichiometric ratio or, if desired, applied in unhydrolyzed form.

Suitable transition metal coupling agents include titanium, zirconiumand chromium coupling agents. The amount of coupling agent can be 1 toabout 10 weight percent of the composition for treating on a totalsolids basis.

Crosslinking materials, such as the aminoplasts discussed above, canalso be included in the composition for treating. Non-limiting examplesof suitable crosslinkers include melamine formaldehyde, blockedisocyanates such as BAYBOND XW 116 or XP 7055, epoxy crosslinkers suchas WITCOBOND XW by Witco Corp., and polyesters such as BAYBOND XP-7044or 7056. The BAYBOND products are commercially available from Bayer ofPittsburgh, Pa. The amount of crosslinker can be about 1 to about 25weight percent of the composition for treating on a total solids basis.

The composition for treating can include one or more emulsifying agentsfor emulsifying components of the composition for treating. Non-limitingexamples of suitable emulsifying agents or surfactants includepolyoxyalkylene block copolymers, ethoxylated alkyl phenols,polyoxyethylene octylphenyl glycol ethers, ethylene oxide derivatives ofsorbitol esters and polyoxyethylated vegetable oils. Generally, theamount of emulsifying agent can be about 1 to about 20 weight percent ofthe composition for treating on a total solids basis.

The composition for treating can also include one or more aqueousdispersible or soluble plasticizers to improve flexibility. Examples ofsuitable non-aqueous-based plasticizers which are aqueous dispersibleplasticizers include phthalates, such as di-n-butyl phthalate;trimellitates, such as trioctyl trimellitate; and adipates, such asdioctyl adipate. An example of an aqueous soluble plasticizer isCARBOWAX 400, a polyethylene glycol which is commercially available fromUnion Carbide of Danbury, Conn. The amount of plasticizer is morepreferably less than about 5 weight percent of the composition fortreating on a total solids basis.

Fungicides, bactericides and anti-foaming materials and organic and/orinorganic acids or bases in an amount sufficient to provide the aqueouscomposition for treating with a pH of about 2 to about 10 can also beincluded in the composition for treating. Water (preferably deionized)is included in the composition for treating in an amount sufficient tofacilitate application of a generally uniform coating upon the strand.The weight percentage of solids of the composition for treatinggenerally can be about 5 to about 20 weight percent.

Staple Fibers and/or Cut Fibers

Staple and/or cut fibers for making the permeable transport layerinclude fibers from polymers such as randomly oriented, cut-staplepolyester fibers. The staple fibers can be loosely associated orarranged in a sheet or batting structure. The hydro-entangling jetsgrasp the staple and/or cut fibers and carry parts of the fibers intoand through the reinforcing fiber layers, thus effecting entanglementand attachment of the underlying reinforcing fiber layers. The staplefibers preferably have a relatively low resistance to bending so thatfibers may be moved downwardly by hydro-entanglement, by mechanicalstructure such as barbed needles, and the like.

Suitable staple fibers are polyester, although glass fibers of reduceddenier meeting the requisite flexibility requirements may be also usedas the staple fibers. The polyester material making up permeabletransport layer comprises a batting of a blend of about 50%-70%Wellman1.5 denier×1.5″ polyester staple fiber, and about 30%-50%Kosa 1.5 denierby 1.5″ long bi-component fiber, crimped and baled. The Kosa fiber givesthe batting web a heat-fusible component, while the Wellman fiberenhances the consistency of the polyester batting and decreases shrinkof the web during heat-fusing. After the blend is mixed, an openerfilamentizes the fibers. The polyester batting in one embodiment has adensity of about 60 grams/m² to about 300 grams/m² and in anotherembodiment about 90 grams/m² to about 150 grams/m². As used herein,“denier” refers to the mass of a fiber divided by its length.

The polyester staple fibers can be replaced with polyethylene batting,such as Honeywell Spectra 1000 or Honeywell Spectra 2000 fiber, or witha high strength polyethylene fiber such as Dyneema SK60 of ToyoboCompany. A polyamide (nylon) batting may also be used. Furthermore, atextured, bi-component or crimped thermoplastic or reactive thermosetstaple fiber, powder, or slurry; or combinations of the above fibers,powders, or slurries such as Kosa K90 and Wellman polyester staplefibers in water or preferably FIT and Wellman polyester staple fibers inwater as used in paper making processes may be employed.

Blends of these staple fibers, powders, and slurries may also be used toachieve desired levels of stiffness and fusability (high-shrink fibersmake the heat-fusion step more dynamic by causing melting kinetics tofocus on the crossover-points of the reinforcement fibers). A blend oflow-melt-flow index and high-strength (high-melt-index) staple fibersachieve a distribution of reinforcing mat strengths, where thecombination of melting kinetics (low-melt-index), and staple-fiberstrength (high-melt-index) was varied to provide increased reinforcingmat integrity (longitudinal strength and resistance to melting at thepultrusion die entrance and within the pultrusion die).

The filament diameter size, in a range of about 9 to 25 microns, and theeffective bundle diameter size, in a range of about in a range of about0.010-inches to about 0.10-inch, can be adjusted to achieve variousdimensions of pultrusion mat. The reinforcement layer can be made verythin, by the use of G150 yarns, or smaller. The strength of the mat, andcorresponding pultrusion, can be increased, but the distribution ofholes (for pultrusion resin wetting) might be lessened, depending on theevenness of the distribution of the G150 yarns. The reinforcementreinforcing fibers may also be increased in size to 110 yield glassfibers resulting in a bulkier reinforcing mat of lower cost.

Circular-Bending Stiffness

The reinforcement mats of the present invention have sufficientstiffness to be pulled without wrinkling and to maintain tracking(parallelism) to minimize distortion during processing, yet retainsufficient suppleness to allow the reinforcing mat to conform to theshape of the perimeter of the pultruded part.

The stiffness of the reinforcing mat is measured according to theprocedure of ASTM D4032-94 Standard Test Method for Stiffness of Fabricby the Circular Bend Procedure. ASTM D4032 evaluates the maximum forcerequired to push the fabric through an orifice in a platform. Themaximum force is an indication of the fabric stiffness or resistance tobending.

The reinforcing mat preferably has a circular-bending stiffness withinthe range of about 4 Newtons (1 kilogram-meter/second²) to about 15Newtons. A reinforcing mat having a value of less than about 4 Newtonsgenerally does not track well in the pre-former ahead of the pultrusiondie for a complex part. A reinforcing mat over about 15 Newtonscircular-bending stiffness has been found to be so stiff that it may bedifficult to shape in the pre-former. A circular-bending stiffness ofover about 15 Newtons also results in a preformed reinforcing mat thathas undesirable wrinkles, or spans depressions, because the stiffreinforcing mat cannot follow the pre-form shaper. The stiffness of thereinforcing mat can be readily adjusted by the concentration and type ofthe binder used.

Mat Thickness

The mat thickness is measured by a tight squeeze of a digital calipersfrom Mitutoyo Corporation. Generally three readings were taken, at threedifferent spots, and the average was recorded.

Mat Tensile Strength

The reinforcing mat preferably has a tensile strength in the 90° ortransverse direction of about 200 lbs./inch as measured per ASTM D76-99.The reinforcing mat has a tensile strength in the 0° or pull directionof at least 3 lbs./inch as measured per ASTM D76-99, and more preferablyat least 6 lbs./inch.

Measurements were taken on samples about 3 inches wide×6 inches long(either longitudinal or transverse) prepared by marking off the area andhand shearing. The samples were each pulled at a rate of about 0.2in/minute until failure. Load and elongation were recorded. The averageof four samples was recorded.

EXAMPLE 1 Thermally Bonded Reinforcing Mat

A reinforcing mat, in a resin matrix, that provides high transversestrength on the exterior or interior surface of a pultruded part such asa sash stile or rail, or a pultruded frame head, sill, or jamb, or otherproducts outside the fenestration industry. The cross-section of thepultruded part is a matrix of thermosetting resin with longitudinal andother-reinforcing fibers in the interior of the parts profile thickness.A first mat layer accounts for about 0.010 inches of the thickness ofthe pultruded part, the longitudinal-reinforcing fiber area is about0.030″ thick, and the opposite mat layer is also about 0.010″ thick. Thelongitudinal reinforcing fibers are oriented in the 0° direction. Theselongitudinal fibers are mostly 675-yield (about 675 yards per pound)glass reinforcing fibers.

The reinforcing mat is a multi-layered structure, with the longitudinaldirection (e.g. the pull direction) designated as the 0°. A first layerincludes a plurality of about 1800-yield glass reinforcing fibers in thetransverse or 90° direction in the plane of the reinforcing mat set atabout 10 courses per inch. A second layer includes of a plurality of anamide, polyester or reactive sheathed fiber glass bundles spaced about 4per inch in about the +/−45° directions in the plane of the reinforcingmat thermally bonded to the transverse glass fibers. A third layerincludes of a plurality of an amide, polyester or reactive sheathedfiber glass bundles spaced about 4 threads per inch in about the 0°direction in the plane of the reinforcing mat thermally bonded to thetransverse glass fibers. A fourth layer includes a plurality ofpolyester fibers that have at least portions thereof which extend in thethickness direction through the third, second and/or first layers toeffect a connection therebetween, with a pre-entangled weight of about32 grams per square meter.

In addition, the reinforcing mat includes holes primarily between thetransverse 1800-yield reinforcing fibers, like sieve-holes in thethrough-thickness direction, with the holes numbering about eighty persquare-inch in a generally rectangular grid pattern. A polyvinylacetate-based binder adheres the multiple layers and/or the intersticeswithin a given layer. The entire reinforcing mat thickness (slightlycompressed during thickness measurement) is approximately 0.010-inches.Further, the reinforcing mat includes a back-side withalternately-spaced 0° fibers as a third layer of a plurality of anamide, polyester or reactive sheathed glass fiber bundles spaced about 4per inch in about the 0° direction in the plane of the mat, thermallybonded to the transverse glass fibers.

EXAMPLE 2 Polyester Stitched Reinforcing Mat

A reinforcing mat, in a resin matrix, that provides high transversestrength on the exterior or interior surface of a pultruded part such asa sash stile or rail, or a pultruded frame head, sill, or jamb, or otherproducts outside the fenestration industry. The cross-section of thepultruded part is a matrix of thermosetting resin with longitudinal andother-reinforcing fibers in the interior of the parts profile thickness.A first mat layer accounts for about 0.010 inches of the thickness ofthe pultruded part, the longitudinal-reinforcing fiber area is about0.030″ thick, and the opposite mat layer is also about 0.010″ thick. Thelongitudinal reinforcing fibers are oriented in the 0° direction. Theselongitudinal fibers are mostly 675-yield (about 675 yards per pound)glass reinforcing fibers.

The reinforcing mat is a multi-layered structure, with the longitudinaldirection (e.g. the pull direction) designated as the 0°. A first layerincludes a plurality of about 1800-yield glass fibers reinforcing fiberssubstantially in the transverse or 90° direction in the plane of themat, set at about 10 courses per inch. A second layer includes aplurality of about 6-denier polyester thread spaced at about 6 threadsper inch in the +45° directions in the plane of the mat is stitched tothe transverse glass fibers. A third layer includes a plurality of abouta 6-denier polyester thread spaced about 6 per inch in about the 0°direction in the plane of the reinforcing mat stitched to the transverseglass fibers. A fourth layer includes of a plurality of about 6-denierfibers that have at least portions thereof that extend in the thicknessdirection through the third, second and/or first layers to effect aconnection therebetween with a pre-entangled weight of about 32 gramsper square meter.

In addition, the reinforcing mat includes holes primarily between thetransverse 1800-yield reinforcing fiber with about eighty persquare-inch in a rectangular grid pattern. A polyvinyl acetate-basedbinder adheres the multiple layers and/or the interstices within a givenlayer. The entire reinforcing mat thickness (slightly compressed duringthickness measurement) is about 0.010-inches.

The back-side of the reinforcing mat includes alternately-spaced 0°fibers as a third layer of a plurality of about a 6-denier polyesterthread spaced about 6 threads per inch in about the 0° direction in theplane of the reinforcing mat and stitched to the transverse glassfibers.

EXAMPLE 3 Glass Fiber Stitched Reinforcing Mat

A reinforcing mat, in a resin matrix, that provides high transversestrength on the exterior or interior surface of a pultruded part such asa sash stile or rail, or a pultruded frame head, sill, or jamb, or otherproducts outside the fenestration industry. The cross-section of thepultruded part is a matrix of thermosetting resin with longitudinal andother-reinforcing fibers in the interior of the parts profile thickness.A first mat layer accounts for about 0.010 inches of the thickness ofthe pultruded part, the longitudinal-reinforcing fiber area is about0.030″ thick, and the opposite mat layer is also about 0.010″ thick. Thelongitudinal reinforcing fibers are oriented in the 0° direction. Theselongitudinal fibers are mostly 675-yield (about 675 yards per pound)glass reinforcing fibers.

The reinforcing mat is a multi-layered structure, with the longitudinaldirection (e.g. the pull direction) designated as the 0°. A first layerincludes a plurality of about 1800-yield fiberglass fibers reinforcingfibers substantially in the transverse or 90° direction in the plane ofthe reinforcing mat set at about 10 courses per inch. A second layerincludes a plurality of glass fiber bundles spaced about 4 per inch inabout the +45° directions in the plane of the mat, stitched to thetransverse fiberglass. A third layer includes of a plurality of about a6-denier polyester thread spaced at about 4 threads per inch in the 0°direction in the plane of the reinforcing mat and stitched to thetransverse glass fibers. A fourth layer includes a plurality ofpolyester fibers that have at least portions thereof that extend in thethickness direction through the third, second and/or first layer toeffect a connection therebetween with a pre-entangled weight of about 32grams per square meter.

The reinforcing mat also includes holes primarily between the transverse1800-yield reinforcing fiber numbering about eighty per square-inch in arectangular grid pattern. A polyvinyl acetate-based binder adheres themultiple layers and/or the interstices within a given layer. The entirereinforcing mat thickness (slightly compressed during thicknessmeasurement) is about 0.010-inches. The reinforcing mat also includes aback-side with alternately-spaced 0° fibers as a third layer of aplurality of a fiberglass bundles spaced about 4 threads per inch in the0° direction in the plane of the reinforcing mat and stitched to thetransverse fiberglass.

EXAMPLE 4 Heat-Fused Polyester Stitched Reinforcing Mat

A reinforcing mat, in a resin matrix, that provides high transversestrength on the exterior or interior surface of a pultruded part such asa sash stile or rail, or a pultruded frame head, sill, or jamb, or otherproducts outside the fenestration industry. The cross-section of thepultruded part is a matrix of thermosetting resin with longitudinal andother-reinforcing fibers in the interior of the parts profile thickness.A first mat layer accounts for about 0.010 inches of the thickness ofthe pultruded part, the longitudinal-reinforcing fiber area is about0.030″ thick, and the opposite mat layer is also about 0.010″ thick. Thelongitudinal reinforcing fibers are oriented in the 0° direction. Theselongitudinal fibers are mostly 250-yield (about 250 yards per pound)glass reinforcing yarn.

The reinforcing mat is a multi-layered structure, with the longitudinaldirection (e.g. the pull direction) designated as the 0°. The firstlayer includes a plurality of about 1800-yield fiberglass fibersreinforcing fibers substantially in the transverse or 90° direction inthe plane of the reinforcing mat set at about 8 courses per inch. Asecond layer includes a plurality of about G150 glass reinforced yarnspaced about 4 threads per inch in about the +/−45° directions in theplane of the reinforcing mat adjacent to the transverse fiberglass. Athird layer includes a plurality of about a 150-denier polyester threadspaced about 5 threads per inch in the 0° direction in the plane of thereinforcing mat and stitched through all the layers. The bobbin threadwas G150 glass reinforced yarn. The fourth layer includes a plurality ofpolyester staple fibers that have at least portions thereof that extendin the thickness direction through the third, second and/or first layerto effect a connection therebetween with a pre-entangled weight of about60 grams per square meter. The polyester staple fibers are heat-fused ata temperature of about 350° to the glass reinforced yarns to act as aninterlaminae-connector to the continuous fiber layers.

The reinforcing mat also includes holes primarily between the transverse1800-yield reinforcing fiber numbering about fifty per square-inch in arectangular grid pattern. A reactive modified latex binder adheres theinterstices between the layers. The entire reinforcing mat thickness(compressed during thickness measurement) is about 0.010″.

EXAMPLE 5 Heat-Fused Smooth-Surface Polyester Stitched Reinforcing Mat

A reinforcing mat, in a resin matrix, that provides high transversestrength on the exterior or interior surface of a pultruded part such asa sash stile or rail, or a pultruded frame head, sill, or jamb, or otherproducts outside the fenestration industry. The cross-section of thepultruded part is a matrix of thermosetting resin with longitudinal andother-reinforcing fibers in the interior of the parts profile thickness.A first mat layer accounts for about 0.010 inches of the thickness ofthe pultruded part, the longitudinal-reinforcing fiber area is about0.030″ thick, and the opposite mat layer is also about 0.010″ thick. Thelongitudinal reinforcing fibers are oriented in the 0° direction. Theselongitudinal fibers are mostly 250-yield (about 250 yards per pound)glass reinforcing yarn.

The reinforcing mat is a multi-layered structure, with the longitudinaldirection (e.g. the pull direction) designated as the 0°. A first layerincludes a plurality of about 1800-yield glass reinforcing fiberssubstantially in the transverse or 90° direction in the plane of thereinforcing mat set at about 8 courses per inch. A second layer includesa plurality of about G150 glass reinforced yarn spaced about 4 coursesper inch in the +/−45° directions in the plane of the reinforcing matadjacent to the transverse glass fibers. A third layer includes of aplurality of a about 150-denier polyester thread spaced about 5 per inchin the 0° direction in the plane of the reinforcing mat and stitchedthrough all the layers mentioned above. The bobbin thread was G150 glassreinforced yarn. A fourth layer includes of a plurality of polyesterstaple fibers that have at least portions thereof which extend in thethickness direction through the third, second and/or first layer toeffect a connection therebetween with a pre-entangled weight of about120 grams per square meter. The polyester staple fibers are heat-fusedat a temperature of about 350° to the glass reinforced yarns to act asan interlaminae-connector to the continuous fiber layers.

The reinforcing mat includes holes primarily between the transverse1800-yield reinforcing fiber numbering fifty holes per square-inch in arectangular grid pattern. A reactive modified latex binder adheres theinterstices between the layers. The entire reinforcing mat thickness(compressed during thickness measurement) is about 0.010″.

EXAMPLE 6 Heat-Fused Stitchless Reinforcing Mat

A reinforcing mat, in a resin matrix, that provides high transversestrength on the exterior or interior surface of a pultruded part such asa sash stile or rail, or a pultruded frame head, sill, or jamb, or otherproducts outside the fenestration industry. The cross-section of thepultruded part is a matrix of thermosetting resin with longitudinal andother-reinforcing fibers in the interior of the parts profile thickness.A first mat layer accounts for about 0.010 inches of the thickness ofthe pultruded part, the longitudinal-reinforcing fiber area is about0.030″ thick, and the opposite mat layer is also about 0.010″ thick. Thelongitudinal reinforcing fibers are oriented in the 0° direction. Theselongitudinal fibers are mostly 250-yield (about 250 yards per pound)glass reinforcing yarn.

The reinforcing mat is a multi-layered structure, with the longitudinaldirection (e.g. the pull direction) designated as the 0°. A first layerincludes a plurality of 1800-yield fiberglass fibers reinforcing fiberssubstantially in the transverse or 90° direction in the plane of thereinforcing mat set at about 8 courses per inch. A second layer includesa plurality of G150 fiberglass yarn spaced about 4 courses per inch inthe +/−45° directions in the plane of the reinforcing mat adjacent tothe transverse glass fibers. A third layer includes a plurality ofpolyester staple fibers that have at least portions thereof which extendin the thickness direction through the third, second and/or first layerto effect a connection therebetween with a pre-entangled weight of about120 grams per square meter. The polyester staple fibers are heat-fusedat a temperature of about 350° to the fiberglass yarns to act as aninterlaminae-connector to the continuous fiber layers.

The reinforcing mat also includes holes primarily between the transverse1800-yield reinforcing fiber numbering about fifty per square-inch in arectangular grid pattern. A reactive modified latex binder adheres theinterstices between the layers. The entire reinforcing mat thickness(compressed during thickness measurement) is about 0.010″.

EXAMPLE 7 Heat-Fused Stitchless Reinforcing Mat, Without 45° ReinforcingFibers

A reinforcing mat, in a resin matrix, that provides high transversestrength on the exterior or interior surface of a pultruded part such asa sash stile or rail, or a pultruded frame head, sill, or jamb, or otherproducts outside the fenestration industry. The cross-section of thepultruded part is a matrix of thermosetting resin with longitudinal andother-reinforcing fibers in the interior of the parts profile thickness.A first mat layer accounts for about 0.010 inches of the thickness ofthe pultruded part, the longitudinal-reinforcing fiber area is about0.030″ thick, and the opposite mat layer is also about 0.010″ thick. Thelongitudinal reinforcing fibers are oriented in the 0° direction. Theselongitudinal fibers are mostly 250-yield (about 250 yards per pound)glass reinforcing yarn.

The reinforcing mat is a multi-layered structure, with the longitudinaldirection (e.g. the pull direction) designated as the 0°. A first layerincludes a plurality of about 1800-yield fiberglass fibers reinforcingfibers substantially in the transverse or 90° direction in the plane ofthe reinforcing mat set at about 8 courses per inch. A second layerincludes a plurality of polyester staple fibers that have at leastportions thereof that extend in the thickness direction through thethird, second and/or first layer to effect a connection therebetween,with a pre-entangled weight of about 100-200 grams per square meter. Thepolyester staple fibers are heat-fused at a temperature of about 350° tothe glass reinforced yarns to act as an interlaminae-connector to thecontinuous fiber layers.

The reinforcing mat also includes holes primarily between the transverse1800-yield reinforcing fiber numbering about fifty per square-inch in arectangular grid pattern. A reactive modified latex binder adheres theinterstices between the layers. The entire reinforcing mat thickness(compressed during thickness measurement) is about 0.010″.

EXAMPLE 8 Heat-Fused Polyester Stitched Reinforcing Mat UsingSilane-Treated Yarn

A reinforcing mat, in a resin matrix, that provides high transversestrength on the exterior or interior surface of a pultruded part such asa sash stile or rail, or a pultruded frame head, sill, or jamb, or otherproducts outside the fenestration industry. The cross-section of thepultruded part is a matrix of thermosetting resin with longitudinal andother-reinforcing fibers in the interior of the parts profile thickness.A first mat layer accounts for about 0.010 inches of the thickness ofthe pultruded part, the longitudinal-reinforcing fiber area is about0.030″ thick, and the opposite mat layer is also about 0.010″ thick. Thelongitudinal reinforcing fibers are oriented in the 0° direction. Theselongitudinal fibers are mostly 250-yield (about 250 yards per pound)glass reinforcing yarn.

The reinforcing mat is a multi-layered structure, with the longitudinaldirection (e.g. the pull direction) designated as the 0°. A first layerincludes a plurality of G37-yield glass reinforced yarns treated withorganosilanes. The yarns of the first layer are substantially in thetransverse or 90° direction in the plane of the reinforcing mat set atabout 8 courses per inch. A second layer includes a plurality of G150fiberglass yarn spaced about 4 courses per inch in the +/−45-degreedirections in the plane of the reinforcing mat adjacent to thetransverse glass reinforced yarns of the first layer. A third layerincludes a plurality of about a 100-denier polyester thread spaced about5 threads per inch in the 0° direction in the plane of the reinforcingmat and stitched through all the layers mentioned above. The bobbinthread was a G150 glass reinforced yarn. A fourth layer includes aplurality of polyester staple fibers that have at least portions thereofwhich extend in the thickness direction through the third, second and/orfirst layer to effect a connection there-between with a pre-entangledweight of about 60 grams per square meter. The polyester staple fibersare heat-fused at a temperature of about 350° to the glass reinforcedyarns to act as an interlaminae-connector to the continuous fiberlayers.

The reinforcing mat also includes holes primarily between the transverse1800-yield reinforcing fiber numbering about fifty per square-inch in arectangular grid pattern. A reactive modified latex binder adheres theinterstices between the layers. The entire reinforcing mat thickness(compressed during thickness measurement) is about 0.010″.

EXAMPLE 9 Heat-Fused Polyester Stitched Reinforcing Mat with Metallic45° Reinforcing Fibers

A reinforcing mat, in a resin matrix, that provides high transversestrength on the exterior or interior surface of a pultruded part such asa sash stile or rail, or a pultruded frame head, sill, or jamb, or otherproducts outside the fenestration industry. The cross-section of thepultruded part is a matrix of thermosetting resin with longitudinal andother-reinforcing fibers in the interior of the parts profile thickness.A first mat layer accounts for about 0.010 inches of the thickness ofthe pultruded part, the longitudinal-reinforcing fiber area is about0.030″ thick, and the opposite mat layer is also about 0.010″ thick. Thelongitudinal reinforcing fibers are oriented in the 0° direction. Theselongitudinal fibers are mostly 250-yield (about 250 yards per pound)glass reinforcing yarn.

The reinforcing mat is a multi-layered structure, with the longitudinaldirection (e.g. the pull direction) designated as the 0°. A first layerincludes a plurality of 1800-yield glass reinforced fibers substantiallyin the transverse or 90° direction in the plane of the reinforcing matset at about 8 courses per inch. A second layer includes a plurality ofabout 0.008″ diameter aluminum wire spaced about 4 wires per inch in the+/−45° directions in the plane of the reinforcing mat adjacent to thetransverse fibers. A third layer includes a plurality of about a100-denier polyester thread spaced about 5 threads per inch in the 0°direction in the plane of the reinforcing mat and stitched through allthe layers mentioned above using a G150 glass reinforced yarn as thebobbin thread. A fourth layer includes a plurality of polyester staplefibers that have at least portions thereof which extend in the thicknessdirection through the third, second and/or first layer to effect aconnection there-between, with a pre-entangled weight of about 60 gramsper square meter. The polyester staple fibers are heat-fused at atemperature of about 350° to the fiberglass yarns to act as aninterlaminae-connector to the continuous fiber layers.

The reinforcing mat also includes holes primarily between the transverse1800-yield reinforcing fiber numbering about fifty per square-inch in arectangular grid pattern. A reactive modified latex binder adheres theinterstices between the layers. The entire reinforcing mat thickness(compressed during thickness measurement) is about 0.010″.

EXAMPLE 10 Heat-Fused Polyester Stitched Reinforcing Mat Without 45°Reinforcing Fibers

A reinforcing mat, in a resin matrix, that provides high transversestrength on the exterior or interior surface of a pultruded part such asa sash stile or rail, or a pultruded frame head, sill, or jamb, or otherproducts outside the fenestration industry. The cross-section of thepultruded part is a matrix of thermosetting resin with longitudinal andother-reinforcing fibers in the interior of the parts profile thickness.A first mat layer accounts for about 0.010 inches of the thickness ofthe pultruded part, the longitudinal-reinforcing fiber area is about0.030″ thick, and the opposite mat layer is also about 0.010″ thick. Thelongitudinal reinforcing fibers are oriented in the 0° direction. Theselongitudinal fibers are mostly 250-yield (about 250 yards per pound)glass reinforcing yarn.

The reinforcing mat is a multi-layered structure, with the longitudinaldirection (e.g. the pull direction) designated as the 0°. A first layerincludes a plurality of about 1800-yield glass reinforcing fiberssubstantially in the transverse or 90° direction in the plane of thereinforcing mat set at about 8 courses per inch. A second layer includesa plurality of about a 100-denier polyester thread spaced about 5 perinch in the 0° direction in the plane of the reinforcing mat andstitched through all the layers mentioned above using a G150 glassreinforced yarn as the bobbin thread. A third layer includes a pluralityof polyester staple fibers that have at least portions thereof whichextend in the thickness direction through the third, second and/or firstlayer to effect a connection there-between, with a pre-entangled weightof about 120 grams per square meter. The polyester staple fibers areheat-fused at a temperature of about 350° to the fiberglass yarns to actas an interlaminae-connector to the continuous fiber layers;

The reinforcing mat also includes holes primarily between the transverse1800-yield reinforcing fiber numbering about fifty per square-inch in arectangular grid pattern. A reactive modified latex binder adheres theinterstices between the layers. The entire reinforcing mat thickness(compressed during thickness measurement) is about 0.010″.

The complete disclosures of all patents, patent applications, andpublications disclosed herein, including those cited in the Backgroundof the Invention section, are incorporated herein by reference as ifindividually incorporated. Various modifications and alterations of thisinvention will become apparent to those skilled in the art withoutdeparting from the scope and spirit of this invention, and it should beunderstood that this invention is not to be unduly limited to theillustrative embodiments set forth herein.

1. A method of making a pultruded part having a uniform cross-section,the method comprising the steps of: orienting a plurality oflongitudinal rovings along a longitudinal axis of a pultrusion die;providing a reinforcing structure comprising a permeable transport webof staple fibers attached to a plurality of first reinforcing fibersoriented in a direction transverse to the longitudinal axis, a pluralityof second reinforcing fibers at a first acute angle relative to thelongitudinal axis, and a plurality of third reinforcing fibers at asecond acute angle that is generally the negative of the first acuteangle, so that the portion of the reinforcing fibers oriented in thedirection generally transverse to the longitudinal direction comprisesat least 40% of a total volume of materials comprising the reinforcingstructure; shaping the reinforcing structure to generally conform with aprofile of the pultrusion die; combining a resin matrix with thelongitudinal rovings and the reinforcing structure in the pultrusion dieso that the longitudinal rovings and the reinforcing structure aresubstantially surrounded by the resin matrix; at least partially curingthe resin matrix in the pultrusion die; and pulling the pultruded partfrom the pultrusion die.
 2. The method of claim 1 wherein the step ofproviding the reinforcing structure comprises arranging a plurality offourth reinforcing fibers parallel to the longitudinal axis.
 3. Themethod of claim 1 wherein the step of providing the reinforcingstructure comprises locating the first reinforcing fibers between thesecond and third reinforcing fibers.
 4. The method of claim 1 whereinthe step of providing the reinforcing structure comprises preparing thefirst, second, and third reinforcing fibers as discrete layers.
 5. Themethod of claim 1 comprising bonding the permeable transport web to thefirst and second reinforcing fibers so that the reinforcing structurehas a thickness of about 0.020 inches.
 6. The method of claim 1 whereinthe step of providing the reinforcing structure comprises preparing thereinforcing structure to have substantially in-plane mechanical anddirectional stability.
 7. The method of claim 1 wherein the step ofproviding the reinforcing structure comprises randomly entangling atleast a portion of fibers in the permeable transport web with the first,second and third reinforcing fibers.
 8. The method of claim 1 whereinthe step of providing the reinforcing structure comprises thermallybonding at least a portion of fibers in the permeable transport web withthe first, second and third reinforcing fibers.
 9. The method of claim 1comprising attaching the first, second and third reinforcing fibers in aspaced-apart configuration with a continuous stitching fiber.
 10. Themethod of claim 1 wherein the step of providing the reinforcingstructure comprises applying a binder to the permeable transport web andthe first, second and third reinforcing fibers.
 11. The method of claim1 wherein the step of providing the reinforcing structure comprisesforming a plurality of perforations through the permeable transport weband between the first, second and third reinforcing fibers.
 12. Themethod of claim 1 wherein the step of providing the reinforcingstructure comprises preparing the permeable transport web with apermeability of at least 180 ft³/minute/ft² as measured according to theprocedure of ASTM D737-96 with a pressure differential of about 0.5 inchcolumn of water.
 13. The method of claim 1 wherein the step of providingthe reinforcing structure comprises preparing the permeable transportweb with a circular bonding stiffness of at least about 4 Newtons asmeasured according to the procedure of ASTM D4032-94.
 14. The method ofclaim 1 wherein the step of providing the reinforcing structurecomprises selecting the first, second and third reinforcing fibers froma group consisting of glass fibers, natural fibers, carbon fibers, metalfibers, ceramic fibers, synthetic or polymeric fibers, composite fibers(including one or more components of glass, natural material, metal,ceramic, carbon, and/or synthetics components), or a combinationthereof.
 15. The method of claim 1 comprising the step of attaching thereinforcing structure to the longitudinal rovings prior to combiningwith the resin matrix.
 16. The method of claim 1 comprising the step ofpositioning a plurality of longitudinal rovings along each surface ofthe reinforcing structure prior to combining with the resin matrix. 17.The method of claim 1 comprising the step of positioning the reinforcingstructure adjacent to at least one surface of the pultruded part. 18.The method of claim 1 comprising the step of positioning thelongitudinal rovings adjacent to at least one surface of the pultrudedpart.
 19. The method of claim 1 comprising the step of arrangingalternating layers of reinforcing structure and longitudinal rovingsprior to combining with the resin matrix.
 20. A method of making apultruded part having a uniform cross-section, the method comprising thesteps of: orienting a plurality of longitudinal rovings along alongitudinal axis of a pultrusion die; providing a reinforcing structurecomprising the steps of; arranging a plurality of first reinforcingfibers in a direction generally transverse to the longitudinal axis in agenerally planar, non-overlapping configuration so that the firstreinforcing fibers do not extend over or cover one another; arranging aplurality of second reinforcing fibers in a direction different than thedirection of the first reinforcing fibers and in a generally planar,non-overlapping configuration so that the second reinforcing fibers donot extend over or cover one another; bonding a permeable transport webof staple fibers to the first and second reinforcing fibers to providelongitudinal strength, shear strength and anti-skew propertiessufficient to substantially maintain the relative orientations of thefirst and second reinforcing fibers when subjected to the pulling forcesencountered during pultrusion, so that the reinforcing structure has athickness of about 0.004 inches to about 0.020 inches and the portion ofthe reinforcing fibers oriented in the direction generally transverse tothe longitudinal direction comprises at least 40% of a total volume ofmaterials comprising the reinforcing structure; shaping the reinforcingstructure to generally conform with a profile of the pultrusion die;combining a resin matrix with the longitudinal rovings and thereinforcing structure in the pultrusion die so that the longitudinalrovings and the reinforcing structure are substantially surrounded bythe resin matrix; at least partially curing the resin matrix in thepultrusion die; and pulling the pultruded part from the pultrusion die.21. The method of claim 20 wherein the step of arranging a plurality ofthird reinforcing fibers in a direction different than the direction ofthe first and second reinforcing fibers and in a generally planar,non-overlapping configuration so that the third reinforcing fibers donot extend over or cover one another.
 22. The method of claim 20 whereinthe step of providing the reinforcing structure comprises randomlyentangling at least a portion of fibers in the permeable transport webwith the first and second reinforcing fibers.
 23. The method of claim 20wherein the step of providing the reinforcing structure comprisesthermally bonding at least a portion of fibers in the permeabletransport web with the first and second reinforcing fibers.
 24. Themethod of claim 20 comprising attaching the reinforcing fibers in aspaced-apart configuration with a continuous stitching fiber.
 25. Themethod of claim 20 wherein the step of providing the reinforcingstructure comprises applying a binder to the permeable transport web andthe first and second reinforcing fibers.
 26. The method of claim 20wherein the step of providing the reinforcing structure comprisesforming a plurality of perforations through the permeable transport weband between the first and second reinforcing fibers.
 27. The method ofclaim 20 wherein the step of providing the reinforcing structurecomprises preparing the permeable transport web with a permeability ofat least 180 ft³/minute/ft² as measured according to the procedure ofASTM D737-96 with a pressure differential of about 0.5 inch column ofwater.
 28. The method of claim 20 wherein the step of providing thereinforcing structure comprises preparing the permeable transport webwith a circular bending stiffness of at least about 4 Newtons asmeasured according to the procedure of ASTM D4032-94.
 29. The method ofclaim 20 wherein the step of providing the reinforcing structurecomprises selecting the first and second reinforcing fibers from a groupconsisting of glass fibers, natural fibers, carbon fibers, metal fibers,ceramic fibers, synthetic or polymeric fibers, composite fibers(including one or more components of glass, natural materials, metal,ceramic, carbon, and/or synthetics components), or a combinationthereof.
 30. The method of claim 20 comprising the step of attaching thereinforcing structure to the longitudinal rovings prior to combiningwith the resin matrix.
 31. The method of claim 20 comprising the step ofpositioning a plurality of longitudinal rovings along each surface ofthe reinforcing structure prior to combining with the resin matrix. 32.The method of claim 20 comprising the step of positioning thereinforcing structure adjacent to at least one surface of the pultrudedpart.
 33. The method of claim 20 comprising the step of positioning thelongitudinal rovings adjacent to at least one surface of the pultrudedpart.
 34. The method of claim 20 comprising the step of arrangingalternating layers of reinforcing structure and longitudinal rovingsprior to combining with the resin matrix.
 35. A method of making apultruded part having a uniform cross-section, the method comprising thesteps of: providing a reinforcing structure comprising the steps of:arranging a plurality of first reinforcing fibers in a directiongenerally transverse to a longitudinal axis of a pultrusion die in agenerally planar, non-overlapping configuration so that the firstreinforcing fibers do not extend over or cover one another; arranging aplurality of second reinforcing fibers along the longitudinal axis andin a generally planar non-overlapping configuration so that the secondreinforcing fibers do not extend over or cover one another; and bondinga permeable transport web of staple fibers to the first and secondreinforcing fibers to provide longitudinal strength, shear strength andanti-skew properties sufficient to substantially maintain the relativeorientations of the first and second reinforcing fibers when subjectedto the pulling forces encountered during pultrusion, so that thereinforcing structure has a thickness of about 0.004 inches to about0.020 inches and the portion of the reinforcing fibers oriented in thedirection generally transverse to the longitudinal direction comprisesat least 40% of a total volume of materials comprising the reinforcingstructure; shaping the reinforcing structure to generally conform with aprofile of the pultrusion die; combining a resin matrix with the thereinforcing structure in the pultrusion die so that the reinforcingstructure is substantially surrounded by the resin matrix; at leastpartially curing the resin matrix in the pultrusion die; and pulling thepultruded part from the pultrusion die.
 36. The method of claim 35wherein the step of providing the reinforcing structure comprisesrandomly entangling at least a portion of fibers in the permeabletransport web with the first and second reinforcing fibers.
 37. Themethod of claim 35 wherein the step of providing the reinforcingstructure comprises thermally bonding at least a portion of fibers inthe permeable transport web with the first and second reinforcingfibers.
 38. The method of claim 35 comprising attaching the reinforcingfibers in a spaced-apart configuration with a continuous stitchingfiber.
 39. The method of claim 35 wherein the step of providing thereinforcing structure comprises applying a binder to the permeabletransport web and the first and second reinforcing fibers.
 40. Themethod of claim 35 wherein the step of providing the reinforcingstructure comprises forming a plurality of perforations through thepermeable transport web and between the first and second reinforcingfibers.
 41. The method of claim 35 comprising the step of attaching thereinforcing structure to a plurality of longitudinal rovings orientedalong the longitudinal axis of the pultrusion die.
 42. The method ofclaim 35 wherein the step of providing the reinforcing structurecomprises selecting the first and second reinforcing fibers from a groupconsisting of glass fibers, natural fibers, carbon fibers, metal fibers,ceramic fibers, synthetic or polymeric fibers, composite fibers(including one or more components of glass, natural material, metal,ceramic, carbon, and/or synthetics components), or a combinationthereof.
 43. The method of claim 35 comprising the step of positioningthe reinforcing structure adjacent to at least one surface of thepultruded part.
 44. A method of making a pultruded part having a uniformcross-section, the method comprising the steps of: orienting a pluralityof longitudinal rovings along a longitudinal axis of a pultrusion die;providing a reinforcing structure comprising a permeable transport webof staple fibers attached to a plurality of first reinforcing fibersoriented in a direction transverse to the longitudinal axis, a pluralityof second reinforcing fibers at a first acute angle relative to thelongitudinal axis, and a plurality of third reinforcing fibers at asecond acute angle that is generally the negative of the first acuteangle, so that the reinforcing structure has a thickness of about 0.004inches to about 0.020 inches; shaping the reinforcing structure togenerally conform with a profile of the pultrusion die; combining aresin matrix with the longitudinal rovings and the reinforcing structurein the pultrusion die so that the longitudinal rovings and thereinforcing structure are substantially surrounded by the resin matrix;at least partially curing the resin matrix in the pultrusion die; andpulling the pultruded part from the pultrusion die.